Complete drop-in set for one engine. Each individual USA made S&S Precision lifter is hand assembled to exact tolerances. Designed for quiet operation rapid pump up and compatible with all stock and high performance applications. USA made. Upgraded replacement for OEM 18538-99C tappet. 99-17(NU)Twin Cam 17-23 M8 00-22(NU)XL 08-12(NU)XR1200 00-10(NU)Buell XB