20 Inch Big Blue Filter Housing: The polypropylene filter housings are ideally used for wide range of applications including residential, commercial and industrial. These are available in 10" and 20" configuration with both slim for low flow and Jumbo for large flow application. The Optional Relief Valve on the inlet of the cap gives ease of air release and prevents vacuum damage and full utilization of the filter elements. The thick side walls give it high pressure ratings. The silicon O rings makes it Leak Proof even at high pressure applications.