Tamiya Hop-Up Options 22046 XV-02/TT-02 Ball Differential Set (39T)This Hop Up Option set is for use with Tamiya XV 02 and TT 02 chassis cars. The Ball Differential option provides your model more stable rear grip thanks to its limited slip differential effect compared to the standard oil filled gear differential. Use this option part for loose surface conditions. Differential Joint A & B x1 each Ball Differential Ring Gear (39T) x1 Bevel Pinion Gear (for 39T gear) x1 Large Ball Diff Alloy Plate (Item 54390) x2