In cases where a simple mechanical protection of the cylinder and electrical resistances with respect to the external environment is required, without limiting the dispersion of heat flows, the Masterwatt produces protective metal grids called Protex, which can have various shapes and sizes depending on the specific needs. At the design level, the product is made with walls or rings, depending on the shape, in aluminized steel or AISI 304 and coupled to an AISI 316 expanded sheet.