These are ingenious door bolts.

The six-sided key is essentially an extruded gear that, when inserted and turned, throws or draws the bolt. When the key is removed, a spring mechanism locks the bolt in position by engaging the rack attached to the bolt.

Installation is straightforward – the cylindrical section fits in a 5/8" diameter hole, and the 3/4" × 1 5/8" face is mortised 1/16" into the door edge. A 1/4" hole serves as the keyhole, and is covered by the included escutcheon.

The small bolt is 1 1/2" long with a 5/16" throw. The large bolt is 2 1/2" long overall, with a 5/8" throw.

Each includes strike plates, mounting screws, escutcheon, and one key. Yellow zinc plated.