Flange Gasket, Full Face, 1/2 in Pipe Size, 3 1/2 in Outside Dia., Bolt Holes 4, 13/16 in Inside Dia., Metal Detectable No, Material of Construction Neoprene, 1/16 in Thickness, -30 Degrees to 250 Degrees Temp. Range (F), Color Black, Standards ASME B16.21, ASTM D2000 BC 607