The Vitoflex cellular rubber tape is available in different cell versions. The F180 is a stiff model that is made from natural rubber. The NF 150 is a self extinguishing model that is made with neoprene that is characterized by a standard hardness rating. The NW 152 is a stiff, self extinguishing unit made of neoprene. Lastly, the CM L is made with EPDM.