GEX Pure Crystal Softening Filter for Cats This product is for Pure Crystal only. Materials: PP, activated carbon, ion exchange resin, PE, polyester Body size (width x depth x height): 15.5 x 15.5 x 1.5 cm Country of origin: Indonesia Body weight: 55g Removes magnesium and calcium from tap water with the action of ion exchange resin! 7 sheets I was using a Pure Crystal water dispenser, but it broke after I bought the filters, so I bought a new machine and am selling these. I used one filter from the pack of 8, so there are 7 remaining.