Description: Material: This 1/28 RC car for gearbox kit uses metal as the material, which is wear resistant, sturdy so that can be reused for a long time. Replacing parts: This remote control cars differential set is suitable to be used as a spare part to replace the old or broke parts of the cars. Wide usage: This metal upgrade bearing replacing part can not only be a repairing accessory, but also can help you to improve your hand-on ability. Easy to install: The upgrade RC cars spare part has simple structure so that can be installed on the remote control cars easily with tools. Compatibility: This RC car modification accessory has a wide compatibility which is replacement for WLtoys 1/28 K969 K979 K989 K999 P929 P939 284131 cars. Specification: Size: for Gearbox: Approx. 25x33x19mm/0.98x1.29x0.74inch. Differential: total length: Approx. 31.5mm/1.24inch; diameter: Approx. 14.8mm/0.58inch. Accessory: total length: Approx. 27mm/1.06inch. Material: Metal. Compatibility: Replacement for WLtoys K969 K979 K989 K999 P929 P939 284131. Color: Blue, red, gold, silver, type 5(show as picture). Note: There might be a few color distortions due to different computer resolutions. There might be a slight error due to different hand measurements. Package Includes: 2 Pieces Differentials. 2 Pieces Gearboxes. 2 Pieces Accessories. 4 Pieces Bearings.