This art-glass disc is made with two very important techniques: the first one is the "sommerso" technique; the fishes and the seaweeds in the middle of the disc are overlaid or "submersed" by a layer of clear crystal, so that the colours inside are magnified. The second technique is called "incalmo" (see glossary) and allows a single piece of glass to be made up of two distinct colours and two distinct techniques. The actual composition of the brighting colours is a jealously-guarded secret, carefully handed down from generation to generation. The diameter of the disc is cm 41 (15.75"). Back-lighting available: an halogen spot is arranged for U.S.A. and European Union. (Max 35 W)