M600 takes 2x 16340 battery - the M300 takes 1x 16340 battery. The M300 Ultra Scout Light® is the epitome of lightweight and power. Its ultra-high-output LED that delivers 1000 lumens of blinding white light. A proprietary TIR lens shapes the recoil-proof LED’s light into a beam with plenty of reach but enough surround light to accommodate peripheral vision, making the M300U ideal for medium to longer-range applications. The rugged M300U attaches quickly and securely to any MIL-STD-1913 rail via its integral thumbscrew clamp, and its included UE07 remote switch assembly allows easy activation by either clicking its push-button or pressing the pressure-activated tape switch. Constructed of lightweight aerospace aluminum, Mil-Spec Hard Anodized finish, and O-ring sealed to keep out the elements, the tough M300U will endure combat-like conditions without any sacrifice in weapon maneuverability. FEATURES - Virtually indestructible ultra-high-output LED generates 1000 lumens of blinding light; produces tactical-level light for .75 hours on a 123A batteries - TIR lens shapes versatile beam with enough reach and surround light for medium- to longer-range operations - Hard-anodized aluminum body, tempered window and O-ring seals make the M600U-A light rugged, durable and combat ready - Easy instant activation via Z68 momentary/constant-on push-button switch or UE07 remote switch assembly - M75 thumbscrew mount attaches quickly & securely to MILSTD- 1913 rails KEY ATTRIBUTES HIGH OUTPUT - 1,000 lumens HIGH RUNTIME - .75 hours PEAK BEAM INTENSITY - 11,300 candela BATTERIES - 1 123A lithium SWITCHING - Tape switch / click tailcap LENGTH - 3.5 in