it works as advertised

Its nominal, 5-micron, cellulose pleat traps fine sediment and some rust particles and prevents these from entering the house plumbing system. Not apparent from the photograph of the product are the use of additional ring seals located at the top and bottom openings to reduce unfiltered water leakage past the filter and into the home.<br /><br />There is a tradeoff between particle trapping size and frequency of filter replacement. Since the 5-micron material traps finer particles than the 20-, 30-, 50-micron filters that are also on the market, you should expect to replace this filter more often than others. I replace it at least every four weeks, whereas others I've used lasted up to six weeks but provided less sediment protection.