Pentek S1 # 155001 S-1 Sediment Replacement Water Filter Cartridge Compatible With Culligan, Ametek, US Filter, Plymouth, Kleen Plus, American Plumber, Bruner & Many Other Brands. S1 20 Micron Pleated Cellulose Sediment Water Filter. 9 3/4" long X 2 1/2" diameter. 24 per case, sold individually. Ametek # 155001. 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 of 24 and save even more.