Why Buy A SureFire Flashlight?


SureFire illumination tools are the finest in the world — compact, rugged, powerful, reliable, efficient. Engineered for maximum performance and precision manufactured, they produce optimal beams — brilliant light with no rings, hot spots, or shadows. That’s why people whose lives may depend on having enough light when they need it, such as military, emergency, and police personnel and outdoors professionals, rely on SureFire. See all our Surefire Flashlights here.

SureFire products feature:
Anodized Aluminum Alloy Construction
Light Output: Candlepower vs. Lumens
Xenon/Halogen Incandescent Lamps
Light-Emitting Diodes LED
HID Lamp
Electronic Power Regulation
Beam Character and Reflector Design
Tempered Pyrex® Windows With Anti-Reflective Coatings
Total Internal Reflection Lenses
Lithium Batteries
Shock Isolation and Protection

Continue reading for more complete technical information on these topics.


Why do SureFire products perform so well in the field? Because we combine advanced design with superior materials and technology, delivering the finest illumination tools possible for extreme situations and environmental conditions. When your life depends on having enough light just when you need it, spend the money to get the best — SureFire.

Anodized Aluminum Alloy Construction

Cross-section diagram of hard anodizing, showing
		surface pores containing trapped dye colorant.SureFire's Multi-axis Computer Numerically Controlled 
		lathes ensure precision-machined components.

SureFire’s aluminum-body WeaponLights are machined from a high-strength aerospace-grade alloy, making them extremely resistant to damage from impact, crushing, or bending, and allowing them to be made as small and light as possible without sacrificing strength. Note: Some of our lights are made of Nitrolon — see following section.

SureFire's Multi-axis Computer Numerically Controlled
		lathes ensure precision-machined components.SureFire’s aluminum-body WeaponLights and flashlights are protected by a finish called anodizing. The anodizing process (from anode, the positive side of an electrical circuit) uses electricity and a chemical bath to “grow” a layer of aluminum oxide on an aluminum surface. Aluminum oxide is the second-hardest substance known to man, exceeded only by diamond, and certain anodized finishes can be made extremely hard, such as the Mil-A-8625 Type III Class 2 military specification finish that SureFire uses.


Some flashlights are made of relatively cheap polymers (plastics) such as ABS. SureFire’s polymer WeaponLight and flashlight bodies are made of Nitrolon, a proprietary high-strength, non-conductive, impact-resistant, glass-filled polyamide nylon polymer. “Glass-filled” means that the polymer matrix has been mixed with fine glass fibers that add rigidity, abrasion resistance, and increased stability at higher temperatures.

Light Output: Candlepower vs. Lumens

The human eye responds most strongly to light nearest the 560 nanometer wavelength,
which is a yellow-green color.Some manufacturers dramatize light output measurements by using candlepower units. They can get away with this because light measurement terminology is unfamiliar to most people. But the basic concepts can be explained as follows:

The science of measuring light with respect to its effect on the human eye — which responds differently according to the wavelength, or color, of that light — is called photometry. Photometry includes measuring light intensity in a particular direction (in units of candlepower or candelas) and total light energy in a particular situation (measured in lumens).

With illumination tools, a candlepower measurement doesn't necessarily indicate total light output. To illustrate this, imagine representing a flashlight's total light output as a bag of sugar. If you pour the sugar onto a table to form a cone and measure the cone's height (representing the brightest part of the flashlight beam as measured in candlepower), you still wouldn't know the total weight of the sugar (representing the total light output as measured in lumens). Conversely, if we shake the table so that the cone settles and becomes rounded, the sugar's weight (lumens) would be the same but the height (brightest part of the beam) has been lowered and spread out.

Now take half the sugar from the demonstration above and put it inside a narrow conical container taller than the loose conical piles we made earlier. Even though this narrow cone's height (candlepower measurement) is greater than the previous cones, it contains only half the sugar (lumens). Reflectors and lenses are analogous to that conical container because they can create a light beam with a high-candlepower "hot spot" that sounds good in advertisements but tells nothing about total light output or light distribution within the beam.

SureFire uses integrating sphere photometers to measure the total lumen output of our illumination tool's, weighted with respect to human eye response. Other manufacturers have begun to follow our lead.

For the record, a lumen is 1/4 π of the total photon (light) flux emitted by a one-candela source. One candela is the luminous intensity of a source whose radiant intensity is 1/683rd of a watt of monochromatic light of wavelength 550 nanometers per steradian. A steradian is a conical figure, or solid angle, whose intersection with a unit sphere covers one unit area. Got it?

Xenon/Halogen Incandescent Lamps

Identical non-SureFire miniature lamps. Left
lamp is unused, right lamp shows tungsten
deposits after several hours of use. Incandescent lamps produce light by using electricity to heat a small coiled tungsten metal wire, which is enclosed within a glass “bulb” filled with special gases, to a high temperature — around 2,500 to 3,000 degrees Celsius — at which point the wire glows white-hot.

The miniature incandescent lamps that SureFire uses in its WeaponLights and flashlights are not typical off-the-shelf products. They are state-of-the-art devices with the following features:

Custom Filaments — The incandescent lamps (“light bulbs”) used in our WeaponLights and flashlights are designed around a specific power supply, light output, and runtime. Filament performance varies according to wire diameter, filament length, filament coil diameter, total coils, and coil-to-coil proximity. Finally, the finished filament must withstand the vibration and G-forces produced by firearms.

SureFire MN21 lamp, showing heavy duty high-output filament. Xenon Gas — The high temperature of the lamp filament causes tungsten atoms to “boil off” and migrate to the cooler glass wall of a lamp, where they condense to form a dark light-blocking layer. Adding a high-pressure inert gas inhibits tungsten boil-off, which reduces the rate of tungsten atom deposition and lengthens the operating life of the lamp. The gas also permits increased filament operating temperature, which in turn increases light output for a given power consumption rate. Argon and krypton are often used as the inert fill gases, but they don’t work as well as xenon. Although xenon is much more expensive, SureFire uses it exclusively to provide optimum lamp performance.

Halogens — To maximize their operating life and light output, some SureFire lamps contain a proprietary mix of halogens, a family of elements that includes fluorine, chlorine, bromine, and iodine. Inside a functioning incandescent lamp, tungsten atoms boil off the filament, migrate toward the cooler areas near the lamp wall, and combine with halogen atoms to form a tungsten halide vapor. This vapor migrates back to the lamp filament, where high temperature breaks it down again into tungsten and halogen atoms. The tungsten atoms are re-deposited on the filament and the oxygen and halogen migrate back toward the bulb wall to re-combine with new boiled-off tungsten atoms. This continuous process, called the halogen cycle, keeps the lamp’s glass walls comparatively clean of light-blocking tungsten deposits.

Incandescent lamps produce a broad spectrum of light (including infrared) and can be made to have a high maximum lumen output, but they are comparatively inefficient users of power, and their lumen output level is effectively non-adjustable.

Light-Emitting Diodes (LEDs)

LED diagram compliments of Lumileds Lighting LLC. An LED (the acronym for Light-Emitting Diode) is a semiconductor “chip” that converts electrical energy directly into light. An LED is called a solid-state light source because it has no gas or liquid components, as do other light sources. The LEDs in SureFire flashlights consists of the emitter chip mounted on a solid base; the chip is attached to electrical leads (wires) that conduct power to it, and it is encased in a clear polymer that is shaped to either focus or disperse the LED’s light in the desired manner.

LEDs generally emit light within a narrow spectral band. In order to produce white light, which consists of the entire visible spectrum combined (or nearly so, as far as the human eye can discern), we use LEDs that emit near-ultraviolet blue light that strikes an upper layer of phosphors. These phosphors absorb the blue light and re-emit white light, in much the same manner that fluorescent light tubes produce white light.

LEDs possess some tremendous advantages over incandescent lamps. First, LEDs can last thousands of hours versus less than fifty hours for high-output incandescent lamps. Second, Photo showing flat surface of high-output LED and surrounding
micro-textured reflector.because LEDs are very robust in construction, and have no mechanically delicate parts such as glass bulbs, filaments, or filament supports, they are extremely resistant to vibration and shock, making them well-suited for the combat environment or for mounting on firearms. Third, LEDs produce virtually no invisible infrared radiation, as opposed to incandescent lamps, which emit over 85% of their output as infrared, and therefore LEDs are much more efficient in producing light than incandescent lamps — an important factor for battery-operated flashlights. And fourth, they will emit light over a wide range of power input making LEDs the natural choice for adjustable-output light sources.

As noted above, there are currently some disadvantages to LED light sources. First, most LEDs emit forward from a flat surface, necessitating more complex reflectors and lenses to produce desirable beam characteristics. Second, because LEDs are susceptible to damage from overheating they have certain thermal design requirements. Therefore, continuous-use LED sources currently have a practical limit of less than 150 lumens. Third, LEDs are difficult to manufacture without some variance in lumen output and color. For this reason, they are tested and sorted by the manufacturer into different “bins” according to output and color. SureFire minimizes such product variability by purchasing LEDs only from the highest-quality bins.

Electronic Power Regulation — SureFire's LED illumination tools contain a rugged, sealed electronic power regulator that supervises the operation of the LED (with the exception of the A2 Aviator, in which the xenon lamp is regulated). This circuitry assesses battery output, monitors system performance, and controls power supplied to the LED. Power regulation provides a more consistent light output for the useable life of the batteries. Although any LED may continue to produce negligible light output for up to several hundred hours, the amount of useful light produced is of a shorter duration. Power regulation circuitry reduces the amount of negligible output and increases the overall duration of useful light output.

HID Lamps

 High Intensity Discharge (HID) lamps do not use a tungsten filament, as do incandescent lamps. Instead they use a clear quartz capsule (an “arc tube”) having electrodes at either end containing high-pressure xenon gas and additional chemical components. When sufficient voltage is applied to the electrodes the gas inside the tube is heated and ionized, enabling it to conduct electricity in the form of an “arc” (basically a sustained electrical spark), and causing it to emit light. When functioning, pressure inside the arc tube rises to several times atmospheric pressure.

HID lamps are both extremely bright and extremely efficient — for an equal power input they produce more than twice the lumens of a tungsten incandescent lamp — and their operating life is also several times that of comparable incandescent lamps. An additional benefit: since they have no filament to break or burn out they are extremely resistant to mechanical shock and vibration. However, they are comparatively large, requires a substantial power source to operate, and their lumen output level is effectively non-adjustable.     

Electronic Power Regulation Electronic power regulation unit provides optimum
power level.

SureFire’s LED illumination tools contain a rugged, sealed electronic power regulator that supervises the operation of the LED (with the exception of the A2 Aviator, in which the xenon lamp is regulated). This circuitry assesses battery output, monitors system performance, and controls power supplied to the LED.  Power regulation provides a more consistent light output for the usable life of the batteries. Although any LED may continue to produce negligible light output for up to several hundred hours, the amount of useful light produced is of a shorter duration. Power regulation circuitry reduces the amount of negligible output and increases the overall duration of useful light output.

Beam Character and Reflector Design

Beam character determines an illumination tool’s suitability for tactical use. It includes light distribution, or the way the beam’s light is apportioned from the center outward, and irregularities, such as dark spots, hot spots, and rings. Irregularities are caused by imprecise reflectors, improperly surfaced reflectors, filament support leg shadows, or “adjustable focusing” that only re-arranges the beam’s defects.

Many illumination tools exhibit inferior beam character. When directed at night on people, objects, or surfaces, they can produce a view that is confusing, misleading, or even alarming. For example, dark or bright spots in a moving beam can be mistaken for moving objects; bright rings tend to seize our attention. Hard-edged beams, like those of theatrical spotlights, can lack the surrounding light necessary for peripheral vision. Closeup photo shows beam-smoothing
micro-texture on a SureFire reflector. This latter effect worsens under stress, when the brain concentrates on central images. A further problem occurs when a hard-edged beam causes people and objects to appear suddenly out of the dark, provoking an instinctive startle response that can trigger a weapon.
Surefire Flashlights
SureFire reflectors are designed to produce optimum beam character. Made from CNC-machined aluminum instead of stamped metal or molded plastic, they exhibit superior strength, heat transfer capabilities, and geometric exactness, the latter permitting precise placement of lamp filaments inside the reflector — within .005" of optimum.

Additionally, SureFire reflector surfaces are covered with tiny ripples that reflect light at slightly different angles, smoothing out beam irregularities and producing a bright central area surrounded by a gradually diminishing corona. This sort of beam is perfect for tactical applications because it clearly illuminates the main object of interest while providing enough light for the observer’s peripheral vision.

Tempered Pyrex® Windows With Anti-Reflective Coatings

On illumination tools, the transparent covering that protects the reflector and lamp from debris and water is called the window (not “lens”). SureFire WeaponLight windows — and those of most SureFire flashlight models — are made of tempered, coated Pyrex glass, as explained below.

Pyrex — Pyrex glass is essentially ordinary glass with boron added, which gives it two desirable properties: it melts at a higher temperature and has a much smaller coefficient of expansion. In illumination tools, the latter quality helps resist cracking when one part of the window is heated more than another, as when an illumination tool is turned on, or when it is suddenly cooled, as when splashed with water.

Tempering — After performing any cutting, shaping, and drilling required to achieve its final shape, a piece of glass is tempered by heating it above the annealing point (about 1,100°F) and then quickly cooling it with forced air. The resulting surface compression stresses give the piece several times the structural strength of common slow-cooled, or annealed, glass.

Anti-reflective Coating — The windows of SureFire illumination tools have a thin coating of material that reduces reflection losses at the glass surface, which increases the net lumen output of the WeaponLight or flashlight.

Total Internal Reflection LensesPrecision-molded TIR lens for the X200A.

The X200A LED Handgun WeaponLight uses a total internal reflection (TIR) lens that is precision molded from a special cyclo-olefin polymer. The lens surrounds the LED, gathering virtually all of its light, which it reflects and refracts forward in an exceptionally tight beam that cannot be duplicated with a reflector.

Lithium Batteries

As a commitment to our customers and products, SureFire sells its own brand of quality 123-type lithium batteries at a very low price. Our WeaponLights and non-rechargeable flashlights use these lithium batteries because of their advantages over alkaline batteries. These advantages are:

Shelf Life — At room temperature, lithium batteries can be stored 10 years and still supply about 70% of their power. Alkaline batteries have a significantly shorter shelf life.
Surefire Flashlights
Temperature Tolerance — Lithium batteries function over a wide temperature range (-60° to 80°C, or -76°F to 176°F), although power is reduced at the extremes. In contrast, alkaline batteries function poorly below freezing and at higher temperatures. The temperature tolerance of lithium batteries also benefits their shelf life. Storing alkaline batteries at higher temperatures can kill them in a few months, but lithium batteries stored for years at similar temperatures can still function effectively.SF 123A Lithium Batteries

Power Density — For a given size (volume), lithium batteries produce much more power than alkaline batteries. For example, given same-sized batteries and the same power load, it would take about 2.5 alkaline batteries to match the power output of one lithium battery.

Weight — For a given size (volume) lithium batteries weigh about half as much as alkaline batteries. For example, an alkaline battery the size of a SureFire SF123 battery would weigh about twice as much.

Voltage — Terminal voltage for lithium batteries is 3 volts compared to 1.5 for alkaline batteries.

Voltage Maintenance — A lithium battery maintains fairly constant voltage for up to 95% of its life, depending on discharge rate. At moderate to high discharge rates, alkaline battery voltage drops rapidly due to internal battery resistance, which wastes power. The large reaction area provided by a lithium battery’s wound-plate construction provides very low internal resistance, ideal for high current loads.

Shock Isolation and Protection

Certain SureFire illumination tools, such as our Special Operations Series flashlights, feature shock-isolated lamp assemblies. This shock isolation acts much like the suspension in an automobile, using springs and dampers to help prevent external forces from damaging lamp parts — particularly filaments. Additionally, a machined-in barrier prevents batteries from slamming forward into the lamp assembly. Note: SureFire illumination tools that use LED light sources don’t need shock isolation because LEDs are inherently resistant to shock and vibration damage.

For exceptionally hard-recoiling weapons such as 12-gauge shotguns and larger caliber rifles, where batteries may be damaged by slamming together, SureFire recommends our special shock-resistant battery sticks. These consist of two, three, or four batteries assembled inside a heat-shrunk polymer sleeve, with each battery physically separated from the others by a load-bearing fiber washer, but electrically connected by a welded metal conductor. For low-recoiling weapons, such as 5.56mm self-loading rifles, standard SureFire SF123 batteries function perfectly.


A fundamental benefit for users of SureFire illumination tools is modularity. This means that many components can be used on different product models, and that certain product models can be reconfigured with available accessories to meet changing needs.

Surefire Flashlight Surefire G2 Flashlight Surefire E2d Defender Flashlight

Surefire 6P Flashlight Surefire Lamps Surefire Surefire G3 Flashlight Surefire Titan Surefire WeaponLights Surefire Digital LED Lights Surefire Pistol Lights Surefire Advanced Rechargeable Lights Surefire Beam Filters Surefire Combat Tactical Lights

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