Sierra - 688-45997-01-00 Yamaha Prop Spacer - 4274A well secured propeller isnt just about performanceits about longevity, efficiency, and smooth operation on the water. The Sierra 18 4274 Prop Spacer is designed to ensure a tight, stable fit between your Yamaha outboards propeller and shaft, reducing vibration, preventing unnecessary wear, and enhancing overall propulsion. Built for durability, this spacer is a simple but essential component that keeps your engine running at peak efficiency.