Machined with the same toughness as Wisecou2019s forged pistons. These compressor sleeves are hard anodized and Teflon coated for low friction and prolonged wear resistance. These sleeves have a smooth radius that tapers down to the specific bore size to make installation of any piston a breeze. These sleeves compress the piston rings smoothly and evenly, greatly reducing the difficulty with installing thin high-performance oil rings.