Product Name: Blue Dwarf Hamsters Exercise Ball Diameter of the ball: 4.72 INCH (Please measure the size of your hamster before purchasing. This product is not suitable for hamsters with larger body size) Vehicle dimensions: Body length: 29.5 cm Body width: 16.5 cm Body height: 14 cm Product material: PP Please note: This product is specially designed for dwarf hamsters. Please read the product instructions carefully before purchasing. We recommend placing small hamsters with a size less than 4 inches.