This is a Single Length of Safety chain with securing hook for mounting to the tongue of your boat trailer or utility trailer. Trailers are required to have these for added safety while towing. You would have two of them, one on either side of the tongue coupler, for attaching to the hitch loops on your tow vehicle. Depending upon your trailers coupler set up, these are either bolted or welded to your trailer. On Boat Trailers, these would be bolted directly to the coupler or tongue of your trailer. It can not be stressed enough how important it is to have safety chains on your trailer. Having properly functioning safety chains will prevent a bad situation from turning into a disastrous situation. This listing is for a Single Length of 30 inch long, 1/4" link diameter, Grade 30 Safety Chain with a Single Hook. This chain has a 5,000 lb Breaking force. The length listed includes the hook.