Pentek FloPlus-20BB Carbon Block Cartridges 4.5" X 20" 0.5 Micron (Full Case)FloPlus Cartridges utilize the benefit of small particle reduction at a flow rate comparable to a 10 micron rated cartridge. This 0. 5 micron 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 filter cartridges are ideal for applications where pressure drop and