Wodent Wheel Sr ? 11" diameter wheel, 3.5" wide running track, 2.6" “mouse-hole shaped” entry holes. Overall height 12.3". Best for lady rats, squirrels, sugar gliders, Syrian or other large hamsters and small hedgies. FOR SUGAR GLIDERS, SMALL HEDGEHOGS, RATS, AND OTHER SMALL PETS Wodent Wheels feature a unique design with a safe solid running surface and a support stand without dangerous pinch areas. The only exercise wheel recommended and approved by the ASPCA during their Seal of Approval program (1999-2006). ATTENTION: THE 11" WODENT WHEEL IS THE ONLY SIZE WHEEL THAT HAS THE NEWEST "SAFETY SHIELD" FOR PROTECTION OF YOUR GLIDERS LEGS AND TAIL - ONLY MANUFACTURED FOR 11" WHEEL AND WE INCLUDE IT WITH YOUR PURCHASE! ($2.50 VALUE!) Rodents are attracted to the wheels entry holes, hamsters avoid broken legs and strangulations, and sugar gliders go absolutely nuts on these wheels. Even rats love running since they dont get their feet hurt and their tails whacked by unsafe axle supports. (Give ratties lots of time ? theyre very cautious!) The semi-enclosed design and the solid rear wall also makes rodents, who are natural “wall-huggers,” feel much safer as they run. 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 low cost, much safer and quieter than conventional wire exercise wheels, and have a clean, simple design using recycled and recyclable plastics.