201C6-3A / HB2430TYD-FS Razor 6-Wire Throttle & Controller Bundle for the Razor E500S, All Versions Quantum 4Front If it's the key for

If it's the key for a CTM 3 and 5 series mobility scooter made prior to 2003 you need

1-1/4" x 5/16"

The securement strap for Pride Silver Star Backpacker AVP

and another knob to clamp down on any optional device on the accessory tube

This 9" rear rim uses a 4-hole mounting plate with pre-installed bearings

201C6-3A / HB2430TYD-FS Razor 6-Wire Throttle & Controller Bundle for the Razor E500S, All Versions Quantum 4Front If it's the key for201C6 3A HB2430TYD FS razor 6 wire throttle & controller bundle, for all versions of the Razor E500S. Replaces the discontinued CT 201 and CT 201C6 control modules. The original controller may come with model number HB2430 TYC4 ROHS, HB2430 TYD4 ROHS CT 201C6, HB2430 TYD4 FS ROHS, or CT 601C6 3. Model numbers vary based on the factory that produced the controller. This controller does not replace the CT101 controller. If your scooter has the CT101