PRW stainless steel rocker arms incorporate an exceptional lightweight design that provides plenty of clearance for large diameter valve springs. These rockers are manufactured from premium quality 15-5ph stainless steel, a superior alloy that is high in Nickel and Chromium. This rigid premium material provides high yield strength to help resist deflection and had extraordinary fatigue resistance. PRW stainless steel rocker arms feature full-cage, friction reducing, needle bearings. The nose rollers and shafts are Cr40 steel, heat-treated and hardened to resist the severity of racing and to minimize 'scrubbing'. Each rocker body is hand-polished, assembled and carefully inspected to provide the customers with some of the finest quality rocker arms available to the racing and performance industry. Requires guide plates.