Limits the width of the opening a sliding doorway or window can open so a child can't get out unnoticed. -To open, just conveyance the pin and open entrance or window as normal. -Sensible for glass and most other surfaces.
These locks are absolute junk! I left it for 48 hours, then locked it. My toddler walked up at hour later and pulled the door wide open, lock falling to the floor. I put it on again for 48 hours and I pulled the door open gently, the lock slid with the door until it popped off and fell to the floor. Wasted weeks of my time waiting for these and the money I paid. Not happy at all!