A martingale is a type of dog collar that provides more control over the animal without the choking effect of a slip collar. A martingale collar is made with two loops. The larger loop is slipped onto the dogs neck and a leash is then clipped to the smaller loop. When the dog tries to pull, the tension on the leash pulls the small loop taut, which makes the large loop smaller and tighter on the neck, thus preventing escape. Features and Specifications: 6x Dog Training Choker 2.5 cm Adjustable Lead Terrific for training dogs. A martingale collar is made with two loops. The larger loop is slipped onto the dogs neck and a leash is then clipped to the smaller loop. When the dog tries to pull, the tension on the leash pulls the small loop taut, which makes the large loop smaller and tighter on the neck, thus preventing escape. Features and Specifications: 6x Dog Training Choker 2.5 cm Adjustable Lead Terrific for training dogs.