The Swivel Tether is our strongest seatbelt tether, featuring a carabiner used by arborists. Its been fully tested, and supports up to 4,500 pounds of force, and if thats not enough for your dog, examine him closely; he may be a horse. And in case your dog is not only strong and restless, but wily, as well, the carabiner locks with a secure screw connection, while the swivel action prevents him from twisting the tether, no matter how active he is.