The HST-Sky lift and slide door has the special feature that the glass pane of the fixed part of the window is directly attached to the cladding and threshold. Thus, the field of view is maximised and more daylight enters the room. The cladding is made from a combination of wood and aluminium, thus affording stability and weather resistance. The door can be made with a size of up to 12 × 2.8 metres and comes with a triple or quadruple glazing unit. Despite its size, it is easy to use, but if desired, the unit can be fitted with an electrical window opener.