iSpring FC15Bx4 10" Big Blue Whole House Water Filter with 4.5" x 10" CTO Carbon Block, 4 Pack Made from high-quality coconut shell carbon Effective reduction of chlorine, and a high removal capacity of unpleasant odors, and tastes Fits 10" Big Blue Water Filter Housings, such as Culligan whole house filter Individually wrapped for freshness 4.5" (Diameter) x 10" (Length)