Industrial Injection GM Performance Cast Pistons For 01-16 Duramax .020 Over - PDM-360.020Duramax . 020 Over Performance Cast Pistons Set Coated Tops and Skirts Deliped Set ( No Valve Relief ) PDM's Ceramic Piston Skirt Coating, is designed to be used, on any rigid or semi rigid surface experiencing sliding, rotating or oscillating friction. This coating will carry loads in excess of 350,000 PSI as well as lubricate at temperatures in excess of 1600f. This coating combines the durability of a ceramic resin with the lubricity of the ceramic