Transoniq Rodent - Semi-Enclosed Exercise Wodent Wheel 'Sr.' 11 inch Size Blue Wodent Wheels are easily disassembled for cleaning and are constructed of tough, safe plastic with a stable base of heavy-gauge painted ( baked-on powder coated) steel. Wodent Wheels are much safer and quieter than conventional wire exercise wheels, and have a clean, simple design using recycled and recyclable plastics Rodents are attracted to the wheel's entry holes which also offer a really nifty effect when watching them run. Hamsters avoid broken legs and strangulations NOT RECOMMENDED for sugar gliders (the center axle can damage their tails) unless you purchase a Wodent Wheel Sugar Glider Tail Guard (sold separately). The semi-enclosed design and the solid rear wall also makes rodents, who are natural 'wall-huggers' feel much safer as they run.