40mm, it is suitable for boat length of 60CM - 100CM -Propeller's diameter is 40mm. Plastic is 4 blades. CNC propeller is 2 blades. Tips: 40mm water thruster's mounting hole -position is 25mm/29mm -We have all these spare parts. -There are bearings inside the water jet, it can hold up the speed of 40000 to 50000rpm. - -If your motor's speed is over 20000 rpm, we suggested that you had better to choose the CNC aluminum propeller. -Strongly recommended the aluminum propeller, it is 150% to 200% higher efficiency than plastic propeller.
-Package Qty: 1 set waterjet thruster with propeller CNC alumunium 2blade or 3blade plastik propellar