HG 19mm Aluminum Ball-Race Rollers for Mini 4WD, ringless design contributes to improved speed. - Model Name: HG 19mm Aluminum Ball-Race Roller Set (Ringless) (Blue) - Model Name: HG 19mm Aluminum Ball-Race Roller Set (Ringless) (Silver) - Compatible Cars: Mini 4WD Pro, Mini 4WD Purchased new and stored at home unopened. There are some corner bends on the backing card. Therefore, please purchase only if you understand this. Thank you for viewing.