These .300" Tall Endure-X Solid Roller Lifters from COMP Cams are engineered to withstand the demands of aggressive cam lobe designs and increased RPM ranges. They feature a wear resistant tool steel axle, precision sorted needle bearings and EDM Oil Injection Technology that guarantees the bearing assembly receives a constant flow of oil. Endure-X Solid Roller Lifters are heat treated, machined to ultra-high tolerances and fully rebuildable.