Features: brand new and high quality Anti-Slip: The wheel has inner anti-slip strips design, prevents your pet from sliping over due to inertia, greatly reduces the risk of injury. Easy to Install: To attache the wheel to the bracket, no for extra tool is required, just tighten the lock by hand. Package: You will receive 1 piece plastic wheels, and 1 piece metal bracket. We offer 4 different sizes of wheels for you to choose. Premium Material: The running wheel is made of high quality plastic material, which is sturdy, safe, non-toxic, eco-friendly and durable. The bracket is made of metal, solid and stable. Silent Working: The plastic wheel works noiseless, keeping quiet while the pet is exercising which does not affect the pet's fragile hearing, nor does it disturb you, providing a funny place for pets to for play and rest. Wide Application: The plastic running wheel is suitable for Hamsters, Gerbils, Rats and other small furry animals. Help your little pet exercise more and develop balance ability and agility. Specifications: Material: Plastic, Metal Color: Transparent, White Diameter: A-16cm/B-20cm/C-24cm/D-27cm Size: A-Diameter Approx.16cm/6.30" B-Diameter Approx.20cm/7.87" C-Diameter Approx.24cm/9.45" D-Diameter Approx.27cm/10.63" Weight: A-Approx.444g B-Approx.450g C-Approx.748g D-Approx.880g Package Includes: 1 Piece Hamster Plastic Running Wheel 1 Piece Metal Bracket note: 1.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!