These are custom made for Outdoor Dog Supply’s Glow Tuff series. There are two sizes: 21″ long and will fit neck sizes of 14″ to 21″, and a 19″ long and will fit neck sizes of 12″ to 19″. These collars are extremely durable and have a tight hole spacing in order to get the best fit on your dog. This collar is a high quality heavy duty ring-in-center strap with a D ring also near the buckle. Comes with a free brass name plate. As with all our collars we have the holes every 1/2 inch for that perfect fit.