They come packaged as a set of 4, with 2 CW rotation and 2 CCW rotation and in a wide range of colors to mix and match to help with orientation.

Specs:
Size: 5045 (5.0" x 4.5")
Color: Blue
Hub: 5mm
Material: Polycarbonate
Weight: 5.2g (each)

Included:
2 x CW rotation
2 x CCW rotation