Aries (AF-20-1042-BB) 20" x 4.5" Big Blue Catalytic Carbon FilterAries Filter Works AF 20 1042 BB 20" x 4. 5" Big Blue Catalytic Carbon Filter High capacity catalytic carbon cartridge engineered for chloramine and hydrogen sulfide reduction in whole house applications Chloramine Removal H2S Reduction 20" x 4. 5" Big Blue Whole House The Aries AF 20 1042 BB uses catalytic grade activated carbon to address contaminants that standard carbon cannot handle effectively. This 20 inch cartridge targets chloramine, hydrogen