The effortless operation of sash units up to 200 kg in weight really makes an impact: as it is closed, the hardware automatically pulls the sash towards the frame. The user hardly needs to exert any manual force or pressure on the sash. The integrated spring mechanism on the rear roller is a sophisticated functional detail. The spring assembly in the mechanism stores the energy produced when opening to door and is thereby tensioned. When the sash is closed, the energy stored is released to enhance sash lift. The functional principle of the roller mirrors that of the familiar technology used on the slide&tilt roller from MACO with its tried-and-tested roller construction (lead-in curve, steering arms and roller unit).