Pentek - NCP-20BB - 20" x 4.5" Pleated Carbon-Impregnated Polypropylene 10 Micron FilterPentek Professional Grade Filtration 20" x 4. 5" Pleated Carbon Impregnated NCP 20BB 10 Micron Filter Dual action sediment and carbon filtration in a single pleated cartridge engineered for whole house, well water, and commercial applications 10 Micron Nominal 20" x 4. 5" Big Blue 1000 Gallon Capacity WHY IT WORKS Carbon impregnated pleats deliver sediment filtration and chlorine reduction without bacterial growth Carbon Impregnated Polyester Non