These kits offer lightweight forging for instant throttle response and maximum torque. Computer engineered piston skirt profiles provide minimal cylinder wall friction. Anti-detonation grooves and ring land diameter eliminates ring blow-by while maximizing engine performance. 4-Stroke Pistons: Dedicated forging for lightweight and superior strength; Race ready dome design for improved combustion flow Armor glide skirt coating provides reduced friction (racing applications only); Piston kit includes piston, rings, wrist pin and circlips Oversize requires cylinder sleeving. Racer's Choice: Pistons are single-ring 2-Stroke or two ring 4-Stroke; Reduced weight and friction with increased power and throttle response; Service intervals may be increased over conventional Wiseco Pistons. 2-Stroke Pro-Lite Pistons:.