Martingale collars have long been used as a method to assist in training dogs. Often described as limited-slip or no-slip collars, the Martingale design provides greater control over your dog versus an ordinary collar and when adjusted properly, is a much safer alternative to the traditional "choke collar" because the properly adjusted Martingale collar limits how tightly it can constrict. The Martingale collar design when fully tightened, should never be adjusted to a size that is less than the size of the dog's neck. The Ultrahund Martingale collar improves on the design by incorporating polymer coated webbing, a strong quick-release buckle and nickel plated chain. Available in a variety of vibrant colors, the Ultrahund Martingale collar comes complete with a glow-in-the-dark "dog tag" for better visibility at night. The Ultrahund large Martingale collar is one inch wide and adjustable to fit a dog's neck size between 18 and 22 inches. The Ultrahund small Martingale collar is 3/4 inches wide and adjustable to fit a dog's neck size between 12 and 16 inches. See sizing chart.Hygienic