First bi-fold windows run on an easy-slide track system and allow wide opening. They’re ideal where homeowners or designers want to capitalise on views, capture cooling summer breezes, or create a unity between indoors and outdoors. First bi-folds carry the weight on a bottom roller so there is no weight pulling down the lintel and causing the panels to jam. Because bi-folds project outwards exercise caution in using them beside decks or walkways. Configurations with even numbered panels are generally used e.g. 2 panels, 2+2 panels, 4 panels and 6 panels. A maximum panel weight of 40kg applies. A maximum height of 1800mm is recommended and a maximum panel width of 900mm.