ST Racing Arrma Aluminum Rear Hex Adapters features set-screws that pin the hex adapters to the axle so the hex adapter does not fall off and cause you to lose the drive pin when you remove your wheels. Aluminum hex adapters are more durable than the stock plastic hexes and will not round off the edges and damage your wheel's hex during a hard impact. Plus, the variety of anodized colors give you the custom options you have been looking for to make your Arrma rig truly one of a kind. Package includes two blue anodized hex adapters.