[Small outer diameter 15CM, inner diameter 14.4CM]
[  Base width 9CM overall height 17.5CM ]  
[  Running wheel outer width 6CM inner width 5.3CM ]  
[Suitable for small rats such as hamsters, three-wire, silver fox, dwarf, in-laws, etc.]

[  Medium size outer diameter 21CM, inner diameter 19.2CM ]  
[Base width 12CM running wheel outer width 8CM inner width 7.2CM overall height 23.5CM]
[Suitable for Xi Shi bear, tiger bear, golden squirrel, rat, juvenile little chinchilla, juvenile little mini hedgehog, honey bag mole, etc.

[Large outer diameter 29CM inner diameter 28CM]
[Base width 14CM Running wheel width 9.5CM Inner width 8.6CM, Overall height 32CM]
[Suitable for adult big totoro, hedgehog, devil squirrel, ferret, guinea pig (guinea pig),etc.]