Some hoses included in the Vulcano® range have a TPU-coated steel spiral, to enhance the maximum adhesion to the wall, such as: Vulcano® M FR, Vulcano® R FR, Vulcano® 09 EST/ET, Vulcano® 15 EST/ET, Vulcano® stone, Vulcano® stone plus, Vulcano® AF plus, Vulcano® 09 AF, Vulcano® 12 ET; in addition, the whole Next series features a TPU-coated steel spiral.