Abstract: A removable device has a screen, two stiles and two rails, connected by elbows. The rectangular screen admits light and air. The two stiles stand mutually parallel, rigid, and perpendicular to the horizon upon installation of the device in an opening. The two rails lie mutually parallel, rigid, and parallel to the horizon. The first elbows receive the rail coaxial with a first spring and the stile coaxial with a second spring while having gripping means. Slightly different, the second elbows have an adjusting means. The stiles and the rails connect to the elbows around the perimeter of the screen.