Guardian Gear Lined Dog Muzzles are the choice of top handlers, trainers and other professionals for safety when working with biting and chewing dogs. Fully adjustable strap and quick-release buckle Crafted in strong nylon fabric Lined with chafe-free inner seams for comfort Material: Nylon with plastic quick release buckle Size: 4 1/2 In Snout Size 0 5 In Snout Size 1 5 1/2 In Snout Size 2 7 In Snout Size 3 8 In Snout Size 4 8 1/4 In Snout Size 5 10 1/4 In Snout Size 5X 10 1/2 In Snout Size 3XL 10 3/4 In Snout Size 4XL Some Recommended Breeds per Size Miniature Dachshunds, Miniature Poodles, Yorkshire Terriers Muzzle Size – 0 Fits Snout Sizes – 4½”” Jack Russell Terriers, Standard Dachshunds, West Highland Whites, Whippets Muzzle Size – 1 Fits Snout Sizes – 5″” Beagles, Border Collies, Cocker Spaniels, Springer Spaniels, Standard Poodles Muzzle Size – 2 Fits Snout Sizes – 5½”” Bull Terriers, Dobermans, German Shepherds, Labrador Retrievers, Setters, Staffordshire Bull Terriers Muzzle Size – 3 Fits Snout Sizes – 7″” Boxers and similar sized breeds with wide, short snouts Muzzle Size – 4 Fits Snout Sizes – 8″” Bloodhounds, Great Danes, Great Pyrenees, St. Bernards, Wolfhounds Muzzle Size – 5 Fits Snout Sizes – 8¼”” Extra large Bloodhounds, Great Danes, Great Pyrenees Muzzle Size – 5XL Fits Snout Sizes – 10¼”” Bull Mastiffs, Rottweilers Muzzle Size – 3XL Fits Snout Sizes – 10½”” Extra large Bull Mastiffs, Rottweilers Muzzle Size -4XL Fits Snout Sizes – 10¾””