Size

Weight Range

Age Range

x-small

6 -12 lbs (3 - 5.5 kg)

0 - 3 months

small

12 - 18 lbs (5.5 - 8 kg)

3 - 9 months

medium

18 - 28 lbs(8 - 12.5 kg)

9 - 30 months

large

28 - 40 lbs (12.5 - 18 kg)

30 - 42 months