Plumbeeze String Wound Polypropylene Cartridges are for a wide range of filtering applications and are manufactured from FDA grade polypropylene. These cartridges are very suitable for potable water filtration. Ideal for removing very fine sediment right through to very coarse sediment, at ambient temperatures. The cartridges are made by diagonally winding a precise pattern of carefully selected fibers on a center core. The pattern is designed to create hundreds of identical, tapered, spiral passageways. During the winding, fibers are combed across the passage and locked in place by succeeding layers. Solid particles are removed by entrapment in this highly efficient filter media. Filtration takes place throughout the entire cartridge, not just on the surface, so large amounts of contaminant are trapped without a sudden rise in pressure caused by surface blinding. By varying the wind pattern, cartridges are fabricated to give a pre-determined micron rating.