Size details [Our size XS] chest: 25cm / 9.84 ", back length: 15cm / 5.91", recommend pet weight: 0.5 - 1Kg (approx.) [Our size S] chest: 30cm / 11.81 ", back length: 18cm / 7.09", recommend pet weight: 1 - 1.5Kg (approx.) [Our size M] chest: 35cm / 13.78 ", back length: 23cm / 9.06", recommend pet weight: 2Kg (approx.) [Our size L] chest: 42cm / 16.54 ", back length: 28cm / 11.02", recommend pet weight: 3Kg (approx.) [Our size XL] chest: 47cm / 18.50 ", back length: 33cm / 12.99", recommend pet weight: 4.5Kg (approx.) [Our XXL Size] chest: 52cm / 20.47 ", back length: 38cm / 14.96", recommend pet weight: 6Kg (approx.)