CH252 helmet

This is the standard issue helmet that the UNSC use for the marines. It was most likely developed at the end of the year 2552 for it isn't shown in Halo:CE.

In Halo 2, both regular Marines and ODST Helljumpers wear versions - marine helmets are painted green, while ODST helmets are painted black, like their combat suits, and feature a faceplate complete with HUD display.