This aluminum outboard propeller is designed as a direct replacement for selected Mercury 40-140 HP outboard engines with a 4-1/4" gearcase and right-hand rotation. Its 3-blade design is built to deliver strong low-torque thrust, reliable control, and smooth everyday boating performance. The high-strength aluminum alloy construction helps resist corrosion, impact, and bending in freshwater and saltwater use. An internal rubber hub helps reduce vibration and noise, while the included M21 interchangeable hub kit supports secure installation.