The handy O-4 Highbeam, named after the brightest star in the universe, weighs a scant 0.3 ounces and emits a powerful beam of light that earns this product its name. The 0-4 Highbeam attaches to a keychain, backpack, jacket, and the list goes on and on... The housing sports high impact, water resistant aluminum with a rubber grip. Single Super-bright L.E.D. bulb never needs replacing. Powered by two replaceable batteries (included).