A Coupler Lock is a security device designed to prevent unauthorized access to a trailer's coupler, which is the part that connects a trailer to a towing vehicle. This lock typically fits over the coupler and is secured with a key or combination, making it difficult for thieves to detach the trailer from the vehicle. These locks are commonly used by individuals who own trailers, such as those for boats, campers, or cargo. By using a coupler lock, owners can enhance the security of their property and reduce the risk of theft when their trailers are parked or stored.