The standard issue Heads Up Display-Smart Helmet comes in two versions. The Mk 3 is made for atmospheric operations and the Mk 5 is self sealing and carries a 28 hour oxygen supply. Both include their own A type battery as a power source and are capable of hooking into external power sources as well, including Mobile Command Units, TacCom equipped vehicles and Naval Field Uniforms. The helmets come standard with an on board Tactical Computer, targeting and weapons management, short range, scramble-secure, multi band/tight beam & broadcasting communications, low light, and full spectrum audio/visual sensors with a 10-30 magnification telescopic and a 40-1000 magnification microscopic view. Each helmet is secured by a bio-signature lockout, requiring retinal scan and a unique operator pass phrase.