TFW Multipurpose Thread Sealant with PTFE is a CALIFORNIA Department of Public Health compliant (Method v1.2), nonhardening soft set, nontoxic thread sealant for sealing and protecting NPT pipe fittings. TFWTM is specially formulated to seal piping used for pressurized air, natural gas, water, and fire sprinkler systems. TFWTM works as well in other fluid and air applications.