Soft but very strong fabric, the Mesh Muzzle allows the dog to breathe and pant normally limiting any unnecessary stress. Easy to fit. Selecting the correct size muzzle for your dog is very important, it is essential that it remain in place whilst fitted. It is recommended that a muzzle is fitted and trialled to ensure a good fit before using in public. Important: Never leave your dog unattended whilst wearing a muzzle. Be sure to get your dog used to their muzzle before leaving it on for any length of time. Size 0 is made to fit a nose 11cm round and 8.5cm in length. Category - Training & Safety.