designer's own words:Solar concentrator consists of circular (spiral) two-sided reflectors. The main particularity of concentrator is that solar rays are focused the same way as in the lens, i.e. the concentrator itself is placed between the light source (sun) and the object, at which rays are focused – that is much more suitable. Circular reflecting elements are constituted of a two-sided mirror spiral belt fixed in special holders. In packed condition the band is firmly twisted and holders are put together. Main advantages of the device – it is cheep, easy and compact. It can be used both as a “solar oven” and in systems of heating and high-effective electric sources. This device is more convenient and safe to use compare with common mirror based solar heaters because it is not require to hang heated dish in the air – it may sit on the table top.