Similar to the design of sliding doors found in automobiles, the design of Lift-slide doors is based on the separation of sliding action and sealing/locking action. Starting from the closed position with the weather-stripping engaged in compression, a 180 degree turn of the door handle unlocks the door and lifts it up by about ½", thereby allowing it to slide easily without rubbing against any weather stripping. As a result, the weather stripping will not wear out prematurely and the doors require no effort to slide. Due to their ease of operation and because of their multi-point locking hardware, lift-slide doors can be built to the size of entire walls. They are the ideal choice when an entire wall is desired to open up to the outdoors such as sun rooms or rooms with a view. Key Features: Easy and effortless to operate. For up to 40' wide openings. Low threshold (wheelchair accessible). High security and energy efficiency, due to multi-point locking hardware (G-U Hardware). Easy installation due to "click-in" door hardware. Solid construction, due to 2 3/8" thick sash and frame, with double mortise-and-tenon joinery. High energy efficiency due to compression weather-seal on all 4 sides. Full range of glazing options (standard glass: 1" overall, tempered). Custom sizes and custom designs, including multi-panel arrangement and large sizes. Made from laminated solid vertical grain Douglas-Fir or a wood of your choice.