Flange Diameter: 5″. Bolt Circle: 4-1/4″. Pilot Diameter: 2-1/2″. Coupling Diameter: 6″. The Drivesaver provides a flexible, nonmetallic barrier between your transmission and propeller shaft. This barrier reduces drivetrain vibration which reduces noise to you, your crew and the water. Absorbs thrust and torque from the propeller shaft, as well as excessive shock from changing gears and high speed planing. Provides an impervious barrier that blocks electrical currents from the water so your engine and transmission are protected from damaging corrosion. Includes: Bushing kits where necessary.