Designed to be installed on most types of doors, this flush bolt is a stylish way to add safety to your home. When the active door is opened, the lever can be moved to the up position, retracting the bolt and allowing the inactive leaf to be opened. When the inactive leaf is closed, the lever can be moved to the down position, pushing the bolt into the strike and securely locking the inactive leaf. Simplified installation for metal frames; round bolt head requires only a punched hole. Strike use is optional. A special guide design and flat-sided bolt tip prevent bolt rotation. Requires a mortised groove in the door 3-1/2 in. long x 7/8 in. deep.