The Twilight Series Outer Filter with Microban® is an Original Equipment filter for the Twilight Series by Master Spas. This filter is used in conjunction with the Twilight Series Eco Pur Filter (X268511) and will work on Twilight Series spas ONLY, dating from 2009-Current. Filter Media made with Microban Antibacterial Protection, and is blue in color. "Pleatco PMA 25" embossed on filter top.