People are continuously looking for ways to maximize their space, as well visually as physically. The system SL77 offers them the opportunity to optimize the utilization of their rooms, drawing the external environment into their homes. Next to the improved space utilization, this innovative system offers the advantage of loads of daylight coming in, as well as an aesthetical design. Next to the functional design, the SL77 is supplemented with a Slim-Line variant, the SL77S, featuring a narrower visible width. Both designs are available in four different door sill solutions: High Performance, Medium Performance, Low Threshold and Flat Bottom Solution. The High Performance option for maximum performance in terms of air, wind and water resistance, Medium Performance combining good air, wind and water resistance with decreased threshold, the Low Threshold option offering a rise of only 18 mm and finally the Flat Bottom solution allowing easy passing and maximum convenience for high traffic. Another practical feature of SL77 is the optional door locking principle which allows to use the first leaf as an entrance door without affecting the folding capacity of the system.