Hot Racing Aluminum 5mm Pinon Gear Caddy. Made with machined aluminum this pinion caddy accommodates pinions with 5mm shafts and can hold up to ten at a time. Incorporated into the design is a 2.5mm hex key to make removal and installation of pinion gears a breeze. Keep all of your pinions organized with this pinion caddy from Hot Racing. Includes one pinion caddy with 2.5mm hex key.