SizeInside diameter (approx.)Outside diameter (approx.)
S11.8in (30cm)23.6in (60cm)
M17.7in (45cm)31.5in (80cm)
L23.6in (60cm)39.4in (100cm)
XL27.6in (70cm)47.25in (120cm)
SizeInside diameter (approx.)Outside diameter (approx.)Breed examples
S11.8in (30cm)23.6in (60cm)Under 20lbs / 9kg - Shih Tzu, French Bulldog, Boston Terrier, Pug
M17.7in (45cm)31.5in (80cm)Under 55lbs / 25kg - Boxer, Cocker Spaniel, Bassett Hound, Bull Terrier
L23.6in (60cm)39.4in (100cm)Under 77lbs / 35kg - Shepherd, Rottweiler, Pitbull Terrier
XL27.6in (70cm)47.25in (120cm)Under 110lbs / 50kg - Shepherd, Rottweiler, Pitbull Terrier, other large dogs