Window Experts Modern frame apertures are getting bigger and the demand for more glass and less vertical divisions by frame members is increasing.Window Experts Heavy Duty Patio Doors can comply with those new challenges with its 2- pane version that can be manufactured up to 5.8 meters wide and up to 3.0 meters tall, accepting a maximum sash weight of 300 kg. The overall outer frame depth of 142 mm housing two 62 mm deep sashes is perfectly suited for modern straight through apertures. The effortless operation of the heavy sashes achieved by using tandem rollers with a high weight carrying capacity,Window Experts solid Aluminum threshold construction and a good gripping D-handle, anchored into the concealed sash steel