Exhaust Bellows for Mercruiser Pre Alpha, Alpha, Gen II and Bravo Stern Drives. Replaces Mercruiser 18654A1. Kit includes bellows and (2) marine grade stainless clamps. This kit is designed to fit #1, R, MR, TRS, Alpha I, Gen II, Bravo I, II, III and Blackhawk models. Item measures approximately 2 1/2" I.D. at each end and approximately 5 1/4" long at rest (new).