Aldex Resin is USA made, non-solvent, strong acid cation resin. It's NSF Gold Certified tested to meet the high standards of NSF certifications. It's a very high quality resin that will outperform any imported resin, it's a durable, reliable, high performance water softener resin. 1 cubic feet of affordable, high quality water softener resin for clean, pure water filtration. Perfect for residential or industrial softeners. Good selectivity and thermotolerant characteristic. Excellent physical and chemical stability. An ion-exchange resin or ion-exchange polymer is a resin or polymer that acts as a medium for ion exchange. Resin is an insoluble microbead material that is porous, so they can trap ions and release other ions in the ion exchange process. Bags and labeling may vary depending on how boxed. Occasionally two half cu. ft. bags will be sent to equal one full cu. ft.