3 PUMPS IN 1: Marineland Maxi-Jet Multi-Use Water Pump acts as a power head, utility pump and circulation pump. MULTIPLE USES: Powers undergravel filters, protein skimmers, calcium reactors and refugiums. CONVERSION KIT: Turns the power head into a prop-style circulation pump. AERATION: Venturi pump allows for fully adjustable aeration. FOUR SIZES: Maxi-Jet 400 (110 to 500 GPH); 600 (160 to 750 GPH); 900 (230 to 1000 GPH); and 1200 (295 to 1300 GPH).