Fits 1984-'17 HD big twin engines, 1986-'18 HD Sportster models, and 1994-'02 Buell. 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. Extremely durable rollers reduce valve stem side thrusting with high lift cams. Superior wear and fatigue resistance even in the most demanding.(2 front and 2 rear rocker arms)