The flagship Xenon Incandescent Flashlight from Surefire. It comes with two light assembly, MN20 (250 lumens) and MN21 (500 lumens). It requires 6 x CR123 batteries using the included MB20 battery holder. Most of the military and armed services in the United State uses this flashlight. Its built to last and the head employs a shock isolating system to protect the bulb from shocks due to drops or sudden impacts.

Rechargeable options for M6.
3xProtected 17670 3.7v Rechargeable + Holder + Welch Allyn 01185 Bi-Pin in Fivemega Socket.
3xProtected 17670 3.7v Rechargeable + Holder + Lumen Factory HO-M6R Bulb.
6xProtected R123A 3.7v Rechargeable + MB20 Holder + Lumen Factory HO-M6R Bulb.
2xProtected 18650 3.7v Rechargeable + Holder + Welch Allyn 01111 Bi-pin in Fivemega Socket.
2xProtected 18650 3.7v Rechargeable + Holder + SF MN15.