Insulation tapes come in plain and twill weaves, with one or both selvedges (hems) able to be reinforced.They are produced in widths from10 – 60 mm and thicknesses from 0.08 to 0.50 mm. In addition to their thickness, the most important factor is the class of thermal resistance determined by the material used. Insulation tapes are made of polyester (Class F thermal resistance) and glass fibres (Class H thermal resistance). Cotton is used less often. New applications with special yarns and aramid fibres have recently been employed.