C.A.T. 15-5 PH stainless steel rockers contain over 15% chromium for the best resistance of corrosion and scaling at elevated temperature. The stainless steel rockers are unparalleled featuring greater strength, durability, and abrasion & erosion resistance for the racing application. The geometric shape at front body of stainless steel rocker allow valve spring up to 1.500" for small block and 1.750" for big blocks in diameter. The larger needle-bearing supported high magnesium fulcrum allows rockers to distribute high load and withstand valve spring load over 1000 PSI. Selfalign feature is available for SBC and SBF. 16 stainless rocker and polylocks come together in package. CAT stainless steel rocker arms are avaliable for 3/8" and 7/16" rocker studs.