Harmsco stainless steel housings utilizes an Up-Flow design which eliminates any air entrapment in the filter housing and stops any bypass of contamination downstream. All of these housings come with electropolished finish for a superior finish and unmatched durability. Harmsco products are extensively tested and meet the highest quality standards. Harmsco also offers housings and filter cartridges with FDA listed materials and are NSF-61 Listed. View NSF Website