Material: High Quality – This choke collar/dog training collar is made of high quality stainless steel. It will not rust, fade, tarnish or crack Size: 3.0mm x 55cm Fully welded links are certified, extra strong links. Ideal for gentle control: it corrects bad dog behavior and stops pulling. Stylish and personalized design: Nine P training collars for obedience or walking. The Training P Starter is used to exercise and train your pet and is safe to use. SIZE MEASUREMENT – Please use a tape measure to measure the soft dog’s neck circumference or part widest of the head, the leash is ideally 3-10cm longer than the size of the dog’s neck. (For example, dog head/neck size is 40cm and dog leash size is 50cm).