GESS FON PSE® e GESS FON PSE GRAFITE® are panels with optimal heat insulation performance made up of a RB 13 plasterboard sheet according to Standard UNI EN 520 (standard, fireproof, waterproof) and a TERMOSTYR® or TERMPOR® sintered expanded polystyrene panel according to Standard EN 13163 EC delayed flame fighting action, Euroclass E.