MB-70 is the modern aluminum system designed to perform elements requiring thermal and accoustic insulation for external building. The assumed depth of the window sections of sash and frame give the effect of one surface from outside after closing- in windows and the effect of flush sash surfaces in the frame- door. The shape of profiles allows to get the smooth and durable constructions of windows and door. System MB-70 features with incridible low value of heat transfer coefficient U thanks to application of the special thermal breaks and seals. It has a great importance in the times when we have increased requirements in energy management and environment protection. The coefficient U for the construction of system MB-70 depending on which profile and accessories were used amounts from 1.5 to 2.39 W/m2K.