Our forged steel roller rocker arms were designed for superior strength and to eliminate the failure-prone stress areas found in some other rockers. S&S roller rockers are forged from 8620 steel, heat-treated, and then shot-peened for additional strength and protection from fatigue. Our rockers also utilize 3/4" long bronze bushings, compared to the more common 1/2" long bushings or needle bearings. The end result is what we believe to be the finest rocker arm available anywhere, for any price. Fits 1984-up big twin engines, 1986-up Harley-Davidson® Sportster® models, and 1991-up Buell® v-twin and Blast® models.