Paul Owens Approved 4- ft Training Tether virtually indestructible. Constructed with seven strand galvanized steel with a plastic coating with a nickel plated swivel bolt snap to prevent tangling. Wire is 3/32-3/16" Swivel Bolts are 2-7/8", Eye Diameter is 1/2" and opening size is 5/16. Each Tether is hand constructed in the USA- Satisfaction Guaranteed