To suit .21 SH Engines only. Will not be suitable for other engines unless meets below requirements: Crankshaft output thread is 6mm in diameter (to accept 6mm thread flywheel axle). 14/15mm long thread up to friction pad (not flywheel). Kit includes: 2 shoe aluminium clutch with spring. 2 pin flywheel. Flywheel axle 6mm thread. Clutch housing 15 teeth includes 2 x 10x5x4 bearings (ODxIDxW). No collect required. Images copyrighted by BlackSmith Products Ltd.