HARD HATS are made of high-density polyethylene. The ratchet suspension models won’t fall off, even when working upside down. The HH1, HH2 and HH4 models meet ANSI Z89.1-1997, Type I, Class E and C.E. EN 397 standards, while the HH3 meets Type II, Class E requirements, with an inner foam liner for off-center (front, back and side) impact. Hard hats will accept most visors and hearing protection devices listed elsewhere (except HH4).