This filter pump is basically two Aquamax pond pumps in one cage. It is remote controlled & can be set to pump any amount of water from zero to its maximum capacity. The Promax filter pump comes with a second inlet which means that you can attach a surface skimmer at the same time as pumping water from the bottom of your pond. Using the remote control supplied one of the two motor units can be adjusted or stopped. Watercourses can be turned down to a trickle at night or filter activity can be increased or decreased by adjusting the flow rate The pump also has two inlets allowing water to be drawn through a surface skimmer or another part of the pond The large strainer basket ensures very low maintenance operation & is capable of accepting up to 8mm particles The Aquamax & Promax range of filter pumps from Oase are unequalled in reliability performance & economy 5 year guarantee