XS: back length 8.7"/22cm; chest girth 11-14"/28-36cm; suggest weight 2.2-4.4lb/1-2kg<br> S: back length 11.4"/29cm; chest girth 12.6-15.7"/32-40cm; suggest weight 4.4-8.8lb/2-4kg <br> M: back length 13"/33cm; chest girth 14-18"/36-46cm; suggest weight 6.6-13lb/3-6kg <br> L：back length 16"/41cm; chest girth 18-22.8"/46-58cm; suggest weight 13-24lb/6-11kg <br> XL: back length 18.9"/48cm; chest girth 22.8-28"/58-72cm; suggest weight 24-39.6lb/11-18kg <br> XXL: backlength22"/56cm; chest girth 27.5-34.6"/70-88cm; suggest weight 39.6-66lb/18-30kg <br> XXXL: back length24.8"/63cm; chest girth 29-37"/74-94cm; suggest weight 66-88lb/30-40kg