Cellular sheet of polycarbonate is a hollow polymeric sheet with the internal structure representing a multilayered construction, filled with longitudinal crosspieces — stiffening ribs. Due to its internal structure it is also called « structured» or « honeycomb» . The structure can have two-, three-layered construction, and its stiffening ribs can form squares, triangles or cross structures. Other names reflecting a structure of material are Multiwall polycarbonate sheet, Cellular polycarbonate. High plasticity and resistance of the material makes possible to receive the sheets with very thin walls ( 0, 3-0, 7 mm) by extrusion way without loss of shock-resistant characteristics and with very small weight at the same time. By means of considerable quantity of empty spaces the weight of a sheet decreases, so, its cost value decreases also. The cellular structure gives visual lightness and airiness to the polycarbonate constructions. Basically, the producers manufacture the panels in the thickness from 4 to 20 mm.