Specifications: Comfortable and strong mouthpiece Prevents barking, chewing, and biting Adjustable to fit all dog sizes Easy and quick to wear Washable at 30 degrees. This comfortable nylon mouthpiece securely holds your dog's jaw to prevent biting, chewing, or barking. The strap allows enough space for your dog to drink and breathe. Place the mouthpiece over your dog's nose. Close the clasps using the adjustable closure and pull the strap. Do not overtighten! There should be enough space to insert one finger between the mouthpiece and your dog's jaw.