HEX-A-JUST Allows for Infinite Valve Timing Adjustability of +/-6 Degrees to Tune for Maximum Engine Performance Output. One Piece Camshaft Sprocket Design Featuring a Billet Eccentric Camshaft Dowel Bushing. Both Billet Steel Sprockets are Heat Treated for Durability. TRUE Roller 0.250" Roller Diameter Chain for Reduced Friction. Includes Captured Needle Camshaft Sprocket Thrust Bearing to Minimize Block Thrust Surface Friction. 3-Piece Sets Hand-Matched to Qualify the Correct Center Distance and Minimize Runout.