An excellent example of a genuine U.S. Gentex SPH-4B flight helmet typically used by helicopter pilots. The SPH-4B is one of the most commonly used military helicopter helmets in the field. The helmet shell is a high-strength, lightweight composite reinforced with epoxy resin. The communications system consists of a boom-mounted microphone M-87/AIC, dual earphones, and a communications cord. It has a fully working dual visor system allowing the user to choose either clear visor or tinted visor. The liner is in excellent shape and uses an energy-absorbing system using polystyrene moulded to conform to the inside of the helmet shell, with the 'B' modification in addition to the polystyrene there is a sort fabric liner for additional comfort. This helmet is in excellent condition with typical usage marks, the 'B' visor also has night vision mounting plus Velcro to the back to support the night vision system. The SPH-4 shell was originally made during the Vietnam War, the DSA (Defense Supply Agency) contract number is visible on the Gentex manufactures label showing a 1971 date, and is sized regular.