Pentek S1-20 # 155303 S1-20 Sediment Replacement Water Filter Cartridge Compatible With Culligan, Ametek, US Filter, Plymouth, Kleen Plus, American Plumber, Bruner & Many Other Brands. S1-20 Pleated Cellulose 20 Micron Sediment Water Filter. 20" long X 2 1/2" diameter. 14 per case, sold individually. Ametek # 155303. S1 series cartridges are economically priced and highly effective at reducing sediment particles down to 20 micron in size. Whole house or point of entry POE filtration to filter out sand, silt, dirt and rust particles that can restrict and plug finer filters, screens or equipment. Order a case and save even more.