SIZES: XS (5-6.5"); S (6.5-8.5"); S+ (7.5-10"); M (9-11"); M+ (10-12"); L (11-13.5"); XL (12-16"). Measure snout tightly and close to the eyes. If between sizes, choose a smaller size. For visual explanation, see below. Bonus Connection Strap for More Secure Fit – For dogs who need more time adjusting to their new muzzle, we’ve added a bonus connection strap that goes over their head for a secure fit that no dog can get out of. Improved design to prevent biting, barking, and unwanted chewing – This muzzle is great for limiting your dog's ability to bite, chew and bark while still allowing your dog to breathe, pant, and drink water. It’s a humane choice for preventing unwanted biting or chewing. See our images for examples. Comfortable Neoprene Padding. Zero Chafing – Save your dog from painful chafing and rough straps. Most muzzles are painful and can rub your dog’s skin raw. GoodBoy makes a comfy, humane muzzle that keeps your dog happy. High Quality Sliders. No Cheap Buckles – The sliders ensure that your dog can’t loosen the straps while giving you more control over the exact fit. Plus, loose ends can be secured with a hook and loop fastener, unlike with buckles. GoodBoy US Muzzle XL Blue