Martingales, a dog owner's best friend, they are designed to get tighter as a dog pulls. This serves different functions, one, it is great for dogs with small heads like Grey Hounds and huskies, preventing them from slipping out. Another use is for safety in triggering situations for reactive, timid or aggressive dogs. Martingales (when fit properly) will prevent your dog from escaping or backing out in a high drive situation due to the cinching function. As for dogs that pull, martingales don't prevent pulling but they are an excellent training tool to for teaching leash manners. Martingales are the number 1 recommended collar style by top trainers. All Collars are sewn on industrial equipment using marine grade thread in Gilbert, Arizona, USA. Details: * High Strength Polyester Webbing (stretch, water, mold, mildew & UV resistant) * All Metal Grizzly Buckle for easy on and off, 84g, 520lb break strength * Rust & Corrosion Resistant Hardware * 1.5" width Martingales are a training tool and not an everyday house collar. Martingales should never be worn unsupervised.