Features: Compatibility:Compatible With WLtoys 1/28 K989 K969 K979 K999 P929 P939 RC Car Upgrades Parts(Red). Material: High Quality Aluminum alloy Weight:13g Packing PE Bag Size: Length 31.5mm Outside Diameter 14.8mm Bearing 6*10*3mm Package List: 2x Metal Ball Differential Gear(Red). Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing,Please allow some small manual measurement errors. After-sales service: If you are not 100% completely satisfied with our products, please feel free to contact us for a refund or replacement!We serve you 24 hours a day！