Pentek - ChlorPlus-20BB - 20" x 4.5" Chloramine Carbon Block FilterPentek Specialty Carbon Block ChlorPlus 20BB 20" x 4. 5" Chloramine Carbon Block Filter Engineered specifically for chloramine reduction in municipal water systems, the ChlorPlus 20BB delivers superior performance over granular carbon with minimal fines and extended capacity in 20" Big Blue housings. 1 Micron 20" x 4. 5" 500,000 Gallon Capacity WHY IT WORKS Built for chloramine removal where GAC falls short Chloramine Specific Formula Catalytic carbon