PureT - CBCM Series - 20" x 4.5" Chloramine Reduction Water Filter - NSF Certified - Carbon Block Chloramine Reduction Filter 0.5 MicronPureT CBCM Series 20" x 4. 5" Chloramine Reduction Carbon Block Filter NSF certified coconut shell carbon designed for chloramine removal and RO membrane protection NSF Certified 0. 5 Micron Coconut Shell Carbon 6 Month Service Life The PureT CBCM Series filter uses compressed coconut shell activated carbon to target chloramines, the disinfectant that destroys reverse osmosis membranes and persists where standard carbon falls short. At 0. 5 micron