This is a Slipper Bushing Set for the Duratrax Evader ST.
These bushings are located on the main shaft.
One Spur Gear Bushing (key #86)
One Small Slipper Bushing (key W)
Assembly onto Evader ST
Spur gear bushing diameter: 9.5mm (0.38")
Slipper bushing diameter: 8mm (0.32")