Purotwist Reverse Osmosis Carbon Filter (Omnipure Filter - Q Series - Twist Off Filter) The Omnipure Q5633 Filter is the carbon replacement filter for both Purotwist 3 stage and 4 stage Reverse Osmosis Systems (the 4 stage system requires two of these filters). As with all Omnipure filters, theﾠQ-Seriesﾠis ideal for use in any situation where better tasting, sediment-free water is required - beverage equipment, R.O. systems, drinking fountains, ice machines, and other point of use applications. Standard media includes granular activated carbon for taste and odor reduction, polypropylene depth filtration for removal of grit and sediment, and polyphosphate to control lime and scaleﾠdeposits. Easy to use Twist Off Filtersﾠ(No tools. No drips. No hassles) TheﾠQ-Seriesﾠis the ultimate "user friendly" inline filter on the market. Replacement of the spent media bed is completed in a matter of seconds by detaching the filter body from a permanentﾠhead with a twist of the wrist. The new filter body is just as easily threaded into ﾠthe head and the replacement is then complete.