Sierra's 18-2733 Water Shutter features a 3.175" length and a 2.500" width. It is designed for use with Mercruiser stern drives. Includes one water shutter per package. It is interchangeable with GLM 89160, Mallory 9-42801, and Mercruiser Stern Drive 92802 and 99370A2. Each Sierra product meets or exceeds the original equipment part it replaces. Fit specific, check part numbers to ensure proper fit.