Large aluminium curtain walls are popular and in high demand in modern architecture. They give buildings a contemporary look and offer the opportunity to incorporate local area influences into the building design. Above all, however, they allow plenty of natural daylight in, minimise the use of artificial light and can be used for passive solar heat generation. To prevent too much UV radiation and heat from entering the building, and to prevent glare, external sun protection elements can be integrated into the curtain wall. The partial integration of the heroal VS Z CS zip screen system into the heroal C 50 curtain wall system, or post-transom curtain walls from other manufacturers, using the heroal GR 25 guide rail is an aesthetically appealing installation of sun protection into post-transom curtain walls that has been thought through down to the smallest detail.