Outboard Water Pump Impeller 334-65021-0 18-8921 for Tohatsu Nissan 9.9HP 15HP 18HP 20HP Boat Motor Number of Blades: 8, Plastic Hub Height: 23.51mm External Impeller Overall Diameter: 41.11mm Internal Shaft Insert Diameter: 13.88mm Net Weight: 12g A External Impeller Overall Diameter: 41.11mm B Height: 23.51mm C Internal Shaft Insert Diameter: 13.88mm Number of Blades: 8 Plastic Hub Net Weight: 12g