These small but crucial parts make up the two outer rings of the Cat Exercise Wheel. If one of these parts is broken, it can cause a wheel to wobble or roll improperly. When ordering Replacement Side Tracks, we highly recommend ordering 1 or 2 units more than you need. If one of the replacements breaks during installation, having a spare could save you a week's worth of shipping time.
These parts are for Generation 4 Wheels only. They will not work on 2nd or 3rd generation wheels.