Scoutlight m620u weapon light, throw lever mount, 500 lumens - SureFire Scout Light M620U Weapon Light, Throw Lever Mount, 500 Lumens

The "Scoutlight M620U Weapon Light, Throw Lever Mount, 500 Lumens" is the best light I have ever bought.
The Swing-Lever clamp provides rapid, secure, solid attachment - even to out-of-spec rails - by moving a single cammed lever, and it detaches quickly. A far-reaching beam with an intense 13,000-candela central area provides significant peripheral illumination, making it ideal for close- to longer-range target. Ergonomic tactical switching click-on and off tailcap and pressure-activated tape switch is easy to use. Integral Swing-Lever™ clamp attaches securely to Picatinny rails.
Powered by two 123A lithium batteries I do'nt know how much time will last the batteries.