Rex Industries manufactures Tiwa Packing P.T.E.F. Impregnated Asbestos Packing. Rex Industries manufactures Quality Sealing Products. The Tiwa Packing P.T.E.F. Impregnated Asbestos Packing is a special quality asbestos fibre braided packing that is impregnated with P.T.F.E. Used for caustic and other corrosive chemicals, solvents, oils, etc, with pH 2-12 TM.