If the formula represents a number of figures: 4h16h4 - this single glass-packet, a glass-packet, which contains two glass thickness of 4 mm with the distance between them in 16 mm. The total thickness of insulating glass unit is 24 mm. When presented with a number of figures: 4h8h4h10h4 - is double glass-packet. He has three glass thickness of 4 mm and the distance between 8 mm and 10 mm. The thickness of insulating glass unit is 30 mm.