Low Pressure Drop – Carbon Block Cartridge 10″x 2.5″ 20 micron. Highest flow Performance carbon block technology. High Performance Coconut Shell 100%. Certified NSF/ANSI Standard 42 – NSF. Certified NSF/ANSI Standard 42. WQA Great Chlorine, taste and Odour Removal Performance tested and verified by Independent laboratory testing. These are very useful when low pressure is a problem and carbon is required for extraction of colour, or odour is a problem. This company only makes carbon cartridges, so their interest is dedicated to producing the finest Coconut Carbon cartridges at sensible prices.