A mildly activated flux for use prior to hot oil fusing. 291 FLUXis formulated without isopropyl alcohol, making it safer to use and store. It is compatible with THERMO FLO? andPRO FUSEfusing/leveling fluids. 291 FLUXcontains ingredients used in the fusing fluids, which results in reduced consumption and prolongs the life of the fusing fluids.