Model: S21
Structure: front 2 rear 4 bearings (bearing)
Material: aluminum alloy hub/rim/stainless steel spokes (copper cap)
Size: 406 (20 inches)

The parameters are as follows:
Wheel diameter 20 inches
Number of openings/holes:
1. The opening of the front wheel is 74mm, 16 holes
 2. The rear wheel set is opened 130mm, 20 holes
Brake: V brake
Color: black/red/silver
Weight: about 1265g
Packing list: 1 pair of front and rear wheels, 1 pair of front and rear quick release, 1 pair of nylon tire pads