Leaving windows open and unlocked is now possible thanks to the Cardinal Gates Window Warden. Developed by PCA Design this unique window guard allows windows to open up to a maximum of 4" but prevents them from opening further. Enjoy fresh air safely, great for children and adults who need supervision. Works on most double hung windows, sliding windows and sliding doors. Not intended for casement, awning, or hopper-type windows. This product is a deterrent, not a substitute for proper adult supervision. Discontinue use when child becomes old enough to defeat product. Each pack includes 2 Window Wardens instructions, and all necessary hardware for installation. Available in off white.