GPO3 Fiberglass Sheet, Red Width and length tolerance is +/- 1/8", Thickness Tolerance +/-.010". UL 940 VO, Track resistant, GPO-3 Sheets are used in electrical applications that require high arc and carbon track resistance as well as flame resistance, physical strength, and moderate heat resistance. Mil-I-24768/6 IEC 60893-1, UP GM 203