General description The Yale PM444 series security door bolts are concealed (mortice fixed) locks designed to enhance home security. They operate with a supplied key, providing added protection by throwing a bolt into the door frame. Finished in polished chrome, these bolts offer a sleek appearance and come with a 2-year guarantee. Technical specifications Finish: Chrome Type: Security bolt Guarantee: 2 years Compatibility and accessories Supplied with 1 key for operation Installation Concealed (mortice fixed) installation into the door Requires fitting into the door and aligning with the door frame for proper operation Usage Operated with the supplied key to lock or unlock the bolt Provides additional security by securing the door into the frame