It is designed for the construction of windows with very high thermal insulation requirements. The structural depth of the sections for frames is 78 mm, and for sashes is 86 mm. The use of 42 mm multi-chamber thermal breaks and a two-component central gasket allows for high thermal insulation. In the PE78N version, the frame heat transfer coefficient is from 1.7 W/m2K. In the warmer PE78N+ version, with closing of the subglass chamber, the Uf is from 1.3 W/m2K.