SureFire M Series Scout Light, LED WeaponLights with TIR Lens and Tumbscrew MountHigh performance, recoil proof LED generates 500 lumens of blinding white light and continues producing tactical level light for 1. 3 hours Total Internal Reflection (TIR) lens creates versatile beam with enough reach for medium range applications and sufficient surround light for peripheral vision Tailcap click switchpartially press for momentary on, click for constant on activation; patented lockout feature prevents accidental activation