ABC HOBBY Electric Outboard Motor (Unused) I believe this item is discontinued. Motor: 540 class (water-cooled compatible) Propeller Diameter: Approximately 36mm / Shaft Diameter: 3.8mm Belt Drive (Cogged Belt) Shielded bearings used in each bearing section * Thrust bearing at the front of the propeller The current motor is a standard 540. For those who understand, thank you.