Lock and Unlock --- Special design of lock and unlock method. Three buttons will need two hands to be locked, and easy operation to be unlocked by just using one hand (2 fingers). Easy and simple for adults, but difficult to use for children. Simple, low-profile design that 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 types of door handles on the market, it has a wide application range because it is more practical and smaller than similar locks on 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 nearby. Please make sure that under the "lock" and "unlock" position, the arm cannot be pushed up or down.