Exotic Nutrition s Silent Runner Glow Wheel 12 Regular is the most innovative wheel on the market for its safety features and whisper-silent spin. The Autoclean Track makes cleaning a breeze by allowing debris to fall through the holes in the track. SIZE: 12 wheel diameter 3.5 wide black track 4 diameter openings 13.5 tall on stand FEATURES: ✔ SAFE - Axle-free construction prevents fur/tail entanglement pet wrap-a-round curvature of the spine and other injuries. ✔ QUIET - Whisper-silent spin using dual-ball bearing technology. ✔ PRACTICAL - Wheel completely disassembles for easy cleaning no nooks for feces to hide in. ✔ SECURE - Designed with a front plate for safety and containment with natural bean-shaped openings. ✔ CONVENIENT - Autoclean Track is an easy way to keep feces and debris from building up on the wheel ✔ EFFECTIVE - Increases ventilation & decreases time spent cleaning the wheel ✔ EASY - Simply install the autoclean track in place of the regular track it takes less than a minute and the wheel will stay cleaner longer ✔ MOUNTS ON CAGE - Easily mounts to the wall of the cage with the cage attachment saving floor space **Please note front plate will appear grey/translucent on arrival. Like all glow-in-the-dark items the front plate needs to sit in a lit room for a few hours for it to glow. It will absorb light during the day then glow in complete darkness at night.