"THRUST WASHER IS CONSTRUCTED BY BONDING WOVEN POLYTETRAFLUOROETHYLENE FIBER FABRIC LINER ON ONE FACE OF WASHER SUBSTRATE.THE SUBSTRATE MAY BE METALLIC,SUCH AS LOW CARBON STEEL,STAINLESS STEEL OR ALUMINUM.MAY ALSO BE A NON-METALLIC SUBSTRATE SUCH AS NEMA GRADE G-10 OR NEMA GRADE C.STANDARD WASHERS ARE MADE WITH G-10 SUBSTRATE"