If your dog is as strong as a wolf, or at least somewhat restless, then they could very well benefit from the EzyDog Double Up Dog Collar Made from EzyDog\'s proprietary soft touch webbing, the collar itself is tested and designed with particular emphasis on durability. The double D Rings truly enhance this, whereby simply attaching the lead to both rings provides extra strength at no expense to canine comfort. The two stainless steel D Rings remove pressure from the easy access buckleComfortable and easy to cleanReflective webbing for night time safetyAccessory D Ring for attaching ID tags etc Size GuideFor best fit measure the neck of your dog.SizeNeck SizeCollar WidthS22 - 29cm (8.5 - 11.5\")12mm (.47\")M29 - 40cm (11.5 - 16\")19mm (.75\")L39 - 59cm (15.5 - 23\")25mm (.98\")XL47 - 71cm (18.5 - 28\")38mm (1.5\")