These lightweight 13mm Aluminum Ball-Race Rollers function superb durability and are usually built with 520 ball bearings to offer smooth rotation. Furthermore, these rollers have actually less friction from the program walls and that can be used for both front side and rear roller setups. This kind of variation makes use of components that have a weight reduced amount of around 30percent thanks to their shape and newly-bored holes. 13mm Aluminum Ball-Race Roller x2 Attachment screws included. Appropriate for all Mini 4WD and Mini 4WD PRO chassis machines. Some framework and systems may require modification.