SADLAK manufactures national match quality precision pistons using premium-grade, heat-treated stainless steel with a highly polished surface. The stainless material and heat-treating operations are both certified to assure that quality and all critical dimensions are individually inspected. These precision pistons are made to the exact GI specifications with all critical dimensions individually inspected. The 420 stainless material and heat-treating operations are both certified to assure quality. The pistons have a highly polished surfaced using a non-contact electro-polishing method that maintains tolerance on the critical diameter and does not "round- over" the edges on the grooves.