Streamlight protac tactical 2L, takes 2 CR123A batteries. 180 lumens on high, 10 lumens on lw (with a 50 hour life on low), with a strobe feature. Very compact, waterproof, rugged, has a a rear button that can be used for momentary on. Excellent as a handheld tac light with a handgun and also a general purpose light on low setting. $40 on Amazon.