The Window Wedge acts as an adjustable Window Stop for Double Hung and Horizontal Sliding windows. Let s parents safely control the height that a window will open. The Window Wedge is made of a durable impact resistant plastic. It attaches easily to the window frame with an adhesive backed strip of Velcro Brand hook and loop material. 3 4" wide and 3" tall. * Easy Hook & Loop Installation- No Tools No Screws No Nails No Damage. * Added Child Safety- Set Window Wedge to a safe opening. (No wider than 4 inches). * Added Home Security- Helps deter unlawful entry from outsiders. Let fresh air in and sleep easier. * Multiple window settings- Adjust Window Wedge for desired opening. * Two Window Wedges per Package.