This part of ISO 13000 specifies the requirements and establishes a system of designation for processed unfilled polytetrafluoroethylene (PTFE) products, which may occur in several forms. The PTFE used to make the semi-finished product is described in ISO 20568-1 and, as provided in ISO 20568-1, may contain up to 1 % of a comonomer. The PTFE used to make the semi-finished product may be virgin, reprocessed or recycled resin. The addition of up to 1,5 % by mass of pigment or colorant is permitted. This part of ISO 13000 allows for five grades based on tensile strength and elongation at break. The semi-finished products can be as-processed (type P) or dimensionally stabilized (type S) and may also have specified electrical properties or other properties when they are required for an application. NOTE References to other standards for semi-finished products made from polytetrafluoroethylene are listed in Annex A for information.