Roger Clark 8mm O Ringed Thermal Phenolic Spacer KitThe RCM O Ringed Thermal spacer kit contains everything required to install our Phenolic Spacers to your Subaru. The kit is designed to aid in the reduction of the air inlet temperatures in the inlet manifold, by isolating the manifold from the heat travelling through from the engine's cylinder heads. Sealing between the spacers, manifold and cylinder heads is by the clever integral double "O ring" design meaning conventional manifold gaskets are no