AXK50P3 is a three pegged axle key designed to fit Kartech 50mm axles.
AXK50P is a two pegged European style axle key the will fit into Kartech 50mm axles as well as OTK axles. It is designed with a lower profile so that the full range of Kartech hubs will slide over the top of the axle key. This is the axle key you require if you wish to use either OTK or European axles in your Arrow kart.

AXK50P3
AXK50P--------