Updated design for 2018! These are now lighter and have built-in hex for easy installation with an adjustable wrench. Billet aluminum drive coupler for the Kawasaki 900/1100 that uses the 750/800 damper. This coupler is for putting a 900/1100 engine into a 750/800 hull. The threads are 24-1.5mm and fit the Kawasaki 1100 crankshaft.