Guardian Angel is well known in the realm of safety products for preventing falls from windows. This product offers premium materials and construction with 4-inch spacing between bars that protect kids from accidental falls. Use the Guardian Angel with a variety of single or double-hung windows as well as sliding and casement windows for a truly versatile protection your family will appreciate. Easy installation with included hardware. Quick release buttons are included for potential emergency situations. Three sizes to choose from including this one. Lifetime Manufacturer Warranty.Works for windows 17-23.