From Yale, the PM444 Door Security Bolt is designed to add an extra layer of security to your door. Concealed within the door as a mortice-fixed bolt, it offers a discreet finish while helping to reinforce the door when locked. Once fitted, the bolt throws into the door frame and is operated using the supplied key, providing added protection for your home. Key features - Concealed, mortice-fixed security door bolt - Bolt throws into the door frame - Key-operated for added security - Supplied with a key - PM444 series