Mercury - Revolution 4 XP Racing Propeller - 4-Blade - 150 to 500 HP - 450R HD Gear Case Outboards Only - 14.6 Dia. 21 Pitch - 48-8M0113940 The Pro Finished Mercury Racing Revolution 4 XP is offered in half-pitch increments designed to fine-tune the engine's RPM maximizing performance. Applicable for Center Console, Bar and workboats. Eligible for Joy Stick Piloting outboards. The REvolution 4 XP Racing Propeller fits 150 to 400 HP Mercury outboard models, and 450R HD gear case outboards only, sterndrive up to 6000 HP.