Smaller size& Lager application range---Suitable for most kinds of door lever handles in the market, it has wide applicable range as it is smaller than the similar locks in the market. "LOCK"&"UNLOCK"---Special design of the "locking"&"unlocking" method. Three buttons will need two hands' operation to get locked, and easy operation to get unlocked by just using one hand (2 fingers). Easy and simple for adult, but hard for children to operate. Simple, unobtrusive design that blends into your room design. Easy Installation---Install the lock directly by just peeling the 3M VHB adhesive tape and placing the lever lock on the door, no drill or tools needed. 3M VHB adhesive tape with strong viscous (Effect will be better after 24 hours) and can be removed easily without any residual, no harm to the door. Why need it---No more kids or pets locking you or themselves in a room; Stop kids from getting into specific rooms like the toilets or the storerooms without adults' supervision; Prevent children from playing with the door and pinching their fingers. WARNING & ATTENTION--- DEFINITELY "UNLOCK" THE SAFETY LOCK WHEN YOUR CHILD ISN'T AROUND. Please make sure under the "LOCKING" and "UNLOCKING" position, the arm can't be pushed up or down.If the door can be opened by pulling the door handle up,the door lever lock can't be used.