Same as the 3600 but outfitted with our Recoil LED module. The 3610 uses a 1 watt LED that's aimed backwards into the reflector. 100% of the light is captured and aimed forward as a tight collimated beam that's as bright as an incandescent. The body is made of tough ABS resin that's corrosion proof and resistant to extreme temperatures. It is powered by 4 AA alkaline cells (included).