The Sure-Flo 100 SqFt Cartridge Filter System includes a new energy efficient 1.2 THP pump that is capable of circulating 4980 gallons per hour, great for pools that hold up to 21,000 gallons. The new Sure-Flo filters are designed to capture debris and clean pool water with consistent performance and energy efficiency. The filter tank top cover features a tightening ring and latch locking system to keep your system air tight, but allow quick filter changes.