There are two cylinders, stop button and three-level switch in the structure, It can ensure the users safety with function of preventing breaking and opening without key inside the house. It is suitable for steel door and wooden door with 30-55MM in thickness.

Usage method:

You shall turn the raised part of key up to aim the red point on the cylinder and insert into plug to open the lock, then you revolve the plug to some position and draw the key.

The latch bolt can be opened by key outside the door or pulled by hand inside the house. If you revolve the stop button after opening, the latch bolt will be inside the lock body and won't come out. Then you can freely open and closed the door.

Round bolt can be two-level swithed by key, the latch bolt can be used separately or meantime.

Various styles and colors are available Mateial; Stainless Steel