Please check the 7th image on the left side of the product webpage and product details, which will guide you on how to train your dog to accept the muzzle. Dogs may feel anxious when first wearing a muzzle and might attempt to remove it or chew through it. NEW DESIGN: This muzzle features an added head strap design that effectively prevents dogs from removing it with their paws. MEASUREMENT: Measure the circumference of your dog's snout and neck. Refer to the size chart to select the appropriate size. Please 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.