Pentek FloPlus-10BB Carbon Block Cartridges 4.5" X 9.75" 0.5 MicronFloPlus Cartridges utilize the benefit of small particle reduction at a flow rate comparable to a 10 micron rated cartridge. This 0. 5 micron carbon block filter cartridge boasts extremely low pressure drops and high flow rates comparable to 10 micron (very open) carbon cartridges. Its efficiency is so high that very small particles can be removed to create cleaner, safer water. These 0. 5 micron carbon block filter cartridges are ideal for