Package Quantity: 78 pieces. Current Type: 71 (includes four tires inside, two axles each, for easier DIY assembly). This is a DIY kit of parts; it does not include a complete car. You will need to provide your own frame, screws, and other necessary components. This gear set includes a wide variety of parts: spindles, single/double bearings, crown gears, pulleys, racks, bevel gears, cup gears, bushings, axles, tires, rubber bands, and more. Featured Gears: 36mm yellow 2mm hole pulley Rack gear Four-wheel drive gear 28-tooth 2mm fan 30-100mm axles 30mm diameter five-spoke wheels! Axle Lengths: 30mm, 50mm, 70mm, 100mm (two of each) Axle Diameter: 2mm Five-Spoke Wheels: 30mm outer diameter, 2mm inner hole (four wheels) Most gears have a 2mm hole (tight or loose fit), except: One 81.5A spindle with a 1.5mm hole Two crown gears with 2.5mm holes One C303A crown gear with a 3mm hole One with a 2.3mm hole and one with a 3.17mm hole.