Pet Dog Adjustable Anti-bite Duck Mouth Style Safety Muzzle S Mouth circumference: 11CM / 4.3'' Suitable for: 5.5-9.9 lb M Mouth circumference: 14.5CM / 5.7'' Suitable for: 9.9- 18.7 lb L Mouth circumference: 16.5CM / 6.5'' Suitable for: 18.7 - 27.5 lb Material: Silicone