The correct size is important for dog rockers as well:
The dog's weight needs to be evenly distributed on the rocker and the runners' radius be fitted so the correct muscles will be used to get the dog to rock.
Dog rockers*
Rockers 600 for dogs up to 10kg
Rockers 800 for dogs over 10kg
*and their humans, for the dog rockers can carry 100kg (600) and 120kg (800). Rockers Training and T.herapy equipment unite longevity, weather proofness and safety for both human and animal.