Children are full of wonder...but sometimes they can become TOO curious and go places that are not safe. DreamBaby's Adhesive Sliding Door Lock helps prevent access to patios, balconies, closets and more... Can be used on most sliding doors and windows. Suitable for glass and most other surfaces. Made from transparent durable material. Gap between the glass & the sliding door/window must be between 8mm & 33mm (3/8" - 1 3/8") to allow door to work properly when latch disengaged. Use on glass, mirror, wood and other surfaces where drilling is impractical. Installs quickly and easily to give you peace of mind. Simply peel, position and press into place. To disengage, simply fold lock down to use windows and doors normally. Please note that locks are not substitute for adult supervision. Never leave child unattended. Includes (2) sliding door locks.