Pentek WP-5 # 155071 WP5 String Wound Sediment Replacement Water Filter Cartridge Compatible With Culligan, Ametek, US Filter, Plymouth, Kleen Plus, American Plumber, Bruner & Many Other Brands. WP-5 Polypropolyne String Wound 5 Micron Sediment Water Filter. 9 7/8" long X 2 1/2" diameter. 24 per case, sold individually. Ametek # 155071. WP Series cartridges are manufactured from a durable polypropylene cord that is wound around a rigid polypropylene core. They are an economical solution to reduce fine sediment, including sand, silt, rust and lime scale particles. WP cartridges are wound in a precise pattern around the core providing a greater surface filtering area. The result is a higher dirt loading capacity and greater efficiency than standard string wound cartridges like the CW. Order a case and save even more.