Watts-MAXCL-FF20 C-Max 20" x 4-5/8” Full Flow Chlorine Reduction Carbon Block FilterThe Watts MAXCL FF20 is a thick walled coconut shell carbon block cartridge engineered for environments where chlorine reduction capacity matters more than anything else. With a 160,000 gallon chlorine reduction rating and 1 micron filtration in a 20" x 4 5 8" form factor, this is the filter you install when you need serious chemical reduction without frequent changeouts. SPECIFICATIONS Watts MAXCL FF20 Technical Details Model Number MAXCL FF20