CHILD SAFETY DEVICE Protect valuable belongings from young children with this durable and effective lock for sliding doors or hung windows. Keep doors and windows open safelyKINDLY REMINDER For our sliding door lock to work effectively on your sliding doors, please remember that the door clearance must be greater than 1.15 cm 0.45 inches and less than 3.2 cm 1.26 inches.SAFE DESIGN This sliding door child lock is installed next to the door shelf and works when dual buttons are pressed simultaneously, stopping the door from sliding and passing each other. This lock is disabled to press the lock cover for unlocking positionEASY INSTALLATION Installing sliding door locks has never been easier, no drilling tools required Simply clean the working area for this lock, peel off the 3M tape and attach this unit to the desired location on your patio sliding doors, closet, cabinets and sliding windowsSTRONG DURABILITY Never worry about sliding window locks breaking with high quality ABS plastic, stainless steel spring and strong 3M adhesive tape. The 3M window lock will not lose efficiency or power even when you routinely open and close your hung windows every day