Floating seals are made of special alloy cast iron. It is exceptionally hard and has superior wear and corrosion resistant capabilities. Metal seals are taper lapped for better lubrication and longer life. It is through-hardened to HRC58 - 65.
O-rings are synthetic Nitrile Butadiene Rubber with excellent resiliency and capability withstands severe temperature from -50 to 110 degree Centigrade or from -58 to 230 degree Fahrenheit. Hardness is set to Hs 66 plus or minus 1.