The SL 97 bi-folding door is available as a bottom-running or top-hung system. The wood/aluminium variant of the SL 97 is particularly notable for its excellent thermal insulation. Laminated wood profiles with a building depth of 96 mm, an additional level of insulation, and triple glazing result in a U-value of 0.80 W/m²K, and enable the system to meet passive house standards. A wide range of opening system variants is available. The system has three sealing levels to provide shelter from the wind and rain, while the aluminium covers on the outside protect the wood profiles from weathering.