BlackHawk Law Enforcement LE Duty Gear Level 2 SERPA Duty Holster. Based on our popular Tactical SERPA Holster, this jacket slot belt loop version gives both the tactical and patrol officer the option of the SERPA's retention and speed in a duty style holster. Whether worn as part of your duty rig, or as a belt mounted holster for tactical use, you get the same great SERPA system, now in a duty holster.