Made of sturdy 5/8" web nylon, and stainless steel curb link chain. The Check-Choke collar is designed to humanely control your dog. If possible, start training your dog with a Check-Choke while still a puppy. Adjust it to fit like a collar with the chain choke fully extended. To correct the dog, give a quick, short jerk to the collar, engaging the choker section. Your dog will react to both the quick jerk and the crisp chain sound. Be sure to praise your dog immediately after it reacts. Endorsed by the humane society and professional handlers. Adjusts for necks 10-14 inches .....'NEW SIZING'