Please check the 7th image on the left side of the product webpage for instructions on how to train your dog to accept the muzzle, as dogs may feel anxious when first wearing muzzles and might attempt to remove them or chew through them. NEW DESIGN: Features an added head strap that effectively prevents dogs from removing the muzzle with their paws. MEASUREMENT: Measure the circumference of your dog's snout and neck. Refer to the size chart to select the appropriate size and double-check measurements before purchasing. HEAD STRAP: If your dog does not attempt to remove the muzzle with its paw, the head strap can be removed for quicker application. ATTENTION: This dog muzzle is not suitable for breeds with short snouts, such as Pitbull mixes, Boxers, Dutch Mastiffs, Affenpinschers, Boston Terriers, and similar breeds.