The McLux III HD45 is a simple twist on light with a battery tube capable of hosting 2xCR123 or 1x18560 cells. The head hosts a Dat2Zip "x2" style converter such as the Wiz2x2. The bulkhead is designed for mounging a Luxeon III or 5W emitter and the reflector is a 45 mm version based on the McR-27 reflective curve. A 4.5 mm thick Lexan window with abrasion resistant coating is captive in the front end between sealing and retaining O-rings. There is no internal or external threaded bezel. There are two bore O-rings to protect the head to battery tube joint from the environment.
With a tether and belt clip installed:
