These are HG (High-Grade) ball bearings to be used on Mini 4WD devices. In comparison to standard ball bearings, they offer more exact components leading to even smoother rotation gears, axles, and much more from your own Mini 4WD automobile.
• HG 620 Ball Bearings x4
• Thickness: 2.5mm.
• appropriate for all Mini 4WD and Mini 4WD PRO automobiles except the Type 1 chassis.