BOROUX foundation black filters are compatible with popular water filtration systems.  They ensure years of reliable service with a lifespan of up to 6,000 gallons per filter (12,000 gallons per pair). The filters, equipped with Stem Saver technology, are reinforced for added durability during handling and cleaning. HSA/FSA Eligible at Checkout. Spring Sale! ($25 off $149+) use code: 25off($55 off $300+) use code: 55off($100 off $500+) use code: 100off