Door Handle With Key On Both Sides. A double cylinder door knob is a door knob that is keyed on both sides of the door or in a place where the door that needs the option of locking on either side of the door. Key unlocks its own knob independently for doors that require keyed security on both sides. Communicating double cylinder lock.
Keyed cylinder in both outside and inside knobs. Keyed entry door knobs have a lock and key mechanism on both sides for safety and security.
Communicating double cylinder lock.
You can also buy a new lock at your hardware store that has two side key entry and replace the whole. Key in either knob locks or unlocks both at the same time for entry doors with glass near the lock including inside office rooms that require security. Some have a button on the inside that you press to lock the door. These door knobs are not very common at all that s for sure.
