Neo for Neoprene. Neoprene is a soft rubber material that is used in wetsuits, and it’s reinforced with nylon webbing for added strength and durability. It makes a great waterproof dog collar that is simple to clean for everyday use or specifically for use in the water. The highest quality materials are used on this waterproof dog collar for added durability. This dog collar is completely waterproof and easy to clean. It features a stainless-steel D-ring which is non-rusting, hook and loop Velcro adjustments make sizing the collar extremely simple and a quick release buckle, so the collar is easy to get on and off. Reflective piping is added for visibility in the dark and an ID clip is available to securely attach your dog's ID tags. S fits necks 13.5 - 15". The collar is 1 1/8” wide. M fits necks 15.5 - 17.25". The collar Is 1 ¼” wide. L fits necks 18 - 20.25". The collar is 1 ¼” wide. XL fits necks 21 - 24". The collar is 1 ¼” wide.