... PTFE Yarn, applicable for seal packing of valves, vessels and pumps of corrosive medium in chemical, medicine, food, petrochemical and powder ... : 4*4mm---40*40mmlength : according to customer requirementFeaturesWidely used in pumps, valves, reciprocating, rotating, mixers etc. Especially used in the environment ... use common PTFE packing.DetailsService Pure PTFE Black Packing/ packing material/with oil