Size 0 fits 3lbs (Teacups)

Size 1 fits 4-5lbs (Toy)

Size 2 fits 6-8lbs (Yorkies) (Small Poms) (Dachshunds)

Size 3 fits 10-15(Medium Poms) (Medium Dachshunds)

Size 4 fits 15-20lbs (Shih Tzu) (Small Maltese)

Size 5 fits 20-25lbs (Maltese Poodles) (Corgis)

Size 6 fits 25-30lbs (medium doodle)

Size 7 ~35lbs