Sierra's 18-2354 Carrier Seal is designed for use with Mercury and Mercruiser engines. Includes one carrier seal per package. It is interchangeable with GLM 12341; Mallory 9-72642; Mercruiser Stern Drive 807929A1, 821759A2, and 821759A4; and Mercury Marine 807929A1, 807929A2, 815922A1, 815922A5, 821759A1, 821759A2, 821759A3, and 821759A4. Each Sierra product meets or exceeds the original equipment part it replaces. Fit specific, check part numbers to ensure proper fit.