1.1 This specification covers nonrigid tubing of vinyl chloride polymer or its copolymers with other materials for use in electrical insulation in three grades, as follows: 1.1.1 This specification covers three grades of nonrigid tubing of vinyl chloride polymer or its copolymers with other materials for use in electrical insulation. Clear transparent, black, white, yellow, green, blue, and red shall be considered standard colo