The Weather Shield Premium Series™ Bi-fold Door is a beautiful solution for both modest to expansive openings. The 2-1/4" thick accordion-style door is available in configurations from two to eight panels and can accommodate openings as wide as 23 feet. Elegant and versatile, the Bi-fold door can be used to divide a room or expand a living space to the outdoors. Units are available as either all-wood or with an extruded aluminum clad exterior and wood interior.