Shelco Filters nominal rated melt-blown depth cartridges are constructed of 100% polypropylene, without additives or surfactants, to remove the risk of foaming to the filtrate. The cartridges’ thermally bonded microfibers create a stable, self-supporting media and this product is NSF approved. Shelco’s melt-blown cartridges are available in standard 2 ½” and 4 ½” (BB Style) diameter configurations with end cap configurations available to fit your specific requirements. Made in the USA!