These lightweight 13mm Aluminum Ball-Race Rollers function superb durability and so are equipped with 520 ball bearings to offer smooth rotation. Furthermore, these rollers have less friction from the course walls and certainly will be properly used for both front side and rear roller setups. This kind of variation utilizes parts which have a weight reduced amount of around 30per cent as a result of their form and newly-bored holes. 13mm Aluminum Ball-Race Roller x2 Attachment screws included. Suitable for all Mini 4WD and Mini 4WD PRO framework devices. Some chassis and figures might need modification.