This is a simple door lock. It can be used on vertical knobs. Suitable for child locks in rental properties, etc. Purchased in September 2022, unused due to incorrect size, but taken out of the bag. Door Stopper Door Lock Set of 2 Stoppers Child Lock Safety Lock Door Lever Lock Fixation Door/Drawer/Door/Cabinet Opening Prohibition Door/Drawer/Door/Cabinet Opening Prohibition Baby Child Finger Pinching Mischief Prevention Earthquake Countermeasures (Black)