COMP Cams Performance Series Solid/Mechanical Lifters with EDM Injection Technology have all of the same high quality features as our Performance Series Solid/Mechanical Lifters with the addition of the EDM oiling hole on the lifter face. These are premium lifters designed specifically for high-end street and race applications. Built to extreme precision tolerances to create the most durable solid lifters available, Performance Series Lifters are engineered to handle elevated, race application valve spring pressures. Each lifter features a precision-ground crown radius and surface finish to extend high-rpm durability and promote compatibility with performance camshafts.