Pentek S1-20BB # 155305 S120BB Big Blue Sediment Replacement Water Filter Cartridge Compatible With Culligan, Ametek, US Filter, Plymouth, Kleen Plus, American Plumber, Bruner & Many Other Brands. S1-20BB Big Blue 20" Pleated Cellulose Sediment Water Filter. 20" long X 4 1/2" diameter. 6 per case, sold individually. Ametek # 155305. 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 water filters, screens or equipment. Order a case and save even more.