Mercury Prop 15.25L32 18D - 48-8M0015401. The Mercury Prop 15.25L32 18D (Part #48-8M0015401) is a precision-engineered stainless steel propeller built for high-performance Mercury outboard and sterndrive engines. With an 18" pitch and a 15.25" diameter, this prop is ideal for boaters who demand optimal acceleration, top-end speed, and fuel efficiency across a range of water conditions.. Key Features. OEM Mercury Quality - Manufactured by Mercury Marine to deliver factory-level performance and re