This series has its origins in the “Universal Range”, which was introduced for the first time in 1912 by the british company “The Steel Manufacturing Co. Ltd.”. The Universal range consisted of three different ranges of profiles, identical in geometry and types, but different in their depth, that classified them into large, medium and small. Depending on the dimensions of the window, the most appropriate series was selected from the static point of view. These three ranges were able to cover any type of window, and in combination with special T-profiles, used as mullions and transoms, for the first time it was also possible to realize curtain walls of any size.
The currently available rage was revised in 1964 and re-coded as “W20”. The three separate ranges were condensed to one medium range, which consisted of 20 profiles able to cover the needs of new windows as well as replace those in historic buildings. Over the decades, some profiles have been abandoned and some new ones have been added, making the range more and more versatile. The depth of the profiles 32 and 37 mm, allows to manufacture various types of openings in different styles, both with single glazing or double glazing with a maximum thickness of 21 mm. Even today, this series is still chosen for a great number of restoration projects worldwide, where the superintendence asks for the original design and proportions of the relevant epoch.