Amazon.com: 3Pack ShareGoo Metal 3.17mm to 5mm Shaft Adapter Change-Over Motor Axle Sleeve Compatible with Hobbywing HSP 540 550 EZRUN-3656 Motor RC Car Boat Plane : Toys & Games
CLIMAX METAL PRODUCTS, Clamp On, 1 in Bore, Step Up Adapter - 5AEZ1|SUA-100 - Grainger
Step Down Adapter - Set Screw, SDA Series (Inch) | Climax Metal Products | MISUMI