Narrow Active Differential set for XB2. The initial XRAY Active Differential is a superior, adjustable front gear differential for XB2 . . . vastly enhancing the buggy's rate and handling characteristics. The special design of interior components utilizing different angled segments permits the diff gears to interact on-power to boost the forward traction, making it faster and simpler to drive. Although the XRAY Active Differential is a performance option for severe racers who want to gain a benefit on superior rate and handling, it is also of great advantage to drivers of all amounts that want a more predictable and easy-to-drive car in most race conditions. Ball-bearings maybe not included. Notice: When building the Active Diff always utilize all 4 interior satellite gears. Never ever just use 2 internal satellite gears.