A Flush Bolt is a flush-mounted lever-action lock which is fitted to the top and bottom of a hinged door sash, eg. French Doors and Bi-Fold Doors, usually in a concealed position. On activating the Flush Bolts, a concealed rod is secured to either the head and/or the sill of the door to prevent the door being forced.

Bolts mounted in a door to lock a door in place. These bolts slide up into the jamb above the door, and down into the threshold or floor below door. They are used primarily on double doors, where one door is locked in place and the other door is the one mainly used. When needed, the door locked in place can be opened. Flush bolts can also be called slidebolts, which are mounted to the face of the door. Fluch bolts are mounted flush with the edge of the door.

Bolts mounted in a door to lock a door in place. These bolts slide up into the jamb above the door and down into the threshold or floor below the door. They are primarily used on double doors where one door is locked in place and the other door is the one mainly used (active door). When needed the door locked in place with the flush bolts can be opened. Flush bolts are housed in a T-Astragal.

A bolt fitted to the first closing door of a double door set where the opening mechanism of the bolt is covered by the second closing door.