Motorad Engine Coolant Thermostat Gasket Gaskets are made from high quality materials suitable for resistance to high temperatures and engine coolant to maintain a good seal. On adhesive backed gaskets, the backing reduces installation time by ensuring proper alignment and ease of installation. Thermostat seals are precision designed and made from high quality rubber products ensuring an accurate fit and durability for a long lasting seal. Number Of Bolt Holes: 2 Prop 65: WARNING: Cancer and Reproductive Harm - www.p65WARNINGs.ca.gov Inside Diameter: 1.6 IN Material: Paper