Made of 15-5 PH stainless steel?a premium alloy high in nickel and chromium, these rocker arms are the choice of professional racers. Extra rigid (tested at 52,000 pounds/inch) to avoid power-robbing deflection, rockers yield both exceptional strength and fatigue resistance. They're designed to minimize reciprocating weight for more RPM and longer valvetrain life. Race-winning durability comes from extra large trunions and additional needle bearings to better distribute load. Unlike aluminum rockers, Hi-Tech Rockers can be rebuilt. Comp Cams will disassemble, inspect, and replace roller tips, axles, trunions, and bearings.