The 4-track window system gives you a variety of ways to control your enclosure’s environment. Each window has four panels that slide up and down independently. Slide all 4-window panels up or down to open 75% of the area for ventilation. (Conventional glass windows allow only 43% to 49% ventilation.) Slide 1, 2, or 3 panels to provide partial ventilation when the temperature dips. Close all 4 panels to protect you from the elements. The screen covering the entire Eze-Breeze system is fixed in place, giving you protection from insects at all times.