The FM411-4R is a 4-pack cartridge filter set from Filtercon. It is designed for heavy-duty use and is ideal for larger swimming pools. It features a 4-position control valve, and its filter cartridges are reusable and last up to 3 times longer than other cartridges. The filter cartridges are engineered with a strong extra-deep pleat design that increases the filter area and extends filter life. The Filtercon FM411-4R can filter up to 15,000 gallons at a time and is easy to maintain and clean.