This specification covers one type of continuous multifilament carbon fibers in the form of a tow or yarn (when twisted). The weight per unit length of the tow or yarn is governed by the filament count which is identified by the suppliers grade or material designation. Carbon tow or yarn, derived from a polyacrylonitrile precursor, with typical tensile strength over 300 ksi (2068 MPa) and tensile modulus of 50 Msi (345 GPa) for use in general purpose structural composites requiring high modulus and moderately high tensile strength