Forestone Alto Sax Ligature with FVCT tratment. Gold Plated for Selmer Hard Rubber size mouthpieces The FVCT developed by Forestone achieves stress-free metal parts combining two types of process. The sound quality achieved by the players gets definitely improved. FVCT also helps to protect the instrument from corrosion. In order to make a difference between the usual Cryogenic process made by other manufacturers, we divide the process into two steps: Gas and liquid. Combining both cyrogenic baths we ensure the success of the process. Better sound and faster response is what the player would feel.