This leather basket dog muzzle is made for Boston Terriers and Pugs. Size 1 The size 1 will fit most standard size Bostons. The neck stap on the size 1 will fit dogs with a 12 to 14 inch neck. Size 2 The size 2 will fit Large Boston Terriers and most Pugs. The size 2 has a little more room for large Bostons and Pugs that have a wide face. The neck strap will fit dogs with a 13 to 15 inch neck.