Lock and Unlock---Special design of lock and unlock method. Three buttons will need two hands to lock, and easy operation to unlock by just using one hand (2 fingers). Easy and simple for adults, but difficult for children to use. Simple, low-profile design blends in with your room decor. Easy Installation --- Install the lock directly by peeling off the 3M VHB tape and placing the lever lock on the door, without drilling or tools. 3M VHB adhesive tape with strong viscosity (the effect will be better after 24 hours) and can be removed easily without any residue, without damaging the door. Wide range of applications: suitable for most kinds of door handles in the market, it has a wide range of application as it is more convenient and smaller than similar locks in the market. Why need it---more children or pets locking you or themselves in a room; prevent children from entering specific rooms such as restrooms or warehouses without adult supervision; prevents children from playing with the door and pinching their fingers. Tips --- Permanently unlock the safety lock when your child is not around. Please ensure that under the "lock" and "unlock" position, the arm cannot be pushed up or down. Note: The data is all manual measurement, please allow an error of 1 - 3cm, due to the difference in light and display, there will be a certain color difference, depending on the physical object received.