- To accurately match the hub hole of the large-sized propeller of APC with the engine shaft, the shaft hole is accurately determined by the spacer (back side) and the propeller washer with guide (front side).

- APC propeller is high pressure injection molded.

• Because the resin entrance is in the center of the hub, a hole is drilled in the center of the hub after molding.
• Hole drilling with this drill is manual and does not have the dimensional accuracy of injection molding.
• The propeller center can be accurately aligned with the shaft center by inserting this spacer after slightly widening the pilot hole and inserting it with a propeller washer with a guide.

- It is made of super duralumin.