Our strongest seatbelt tether features a locking carabiner used by arborists. Fully tested, it supports up to 4,500 pounds of force. The swivel action allows your dog freedom of movement, and prevents them from getting tangled up in the seatbelt. Screw gate carabiner lock. Swivel action for tangle free mobility. Tether measures 10 inch. Designed to prevent distracted driving, not crash tested.