Big Foot Manufacturing Co. produces filters that designed to be used as initial filters on the suction side of pumps using surface water sources. The 40G and 80G, rated at 40 gallons and 80 gallons per minute, respectively, are made of heavy-duty PVC, plastic and stainless steel. The 40G filter uses a 6-inch diameter outside screen and a 2-inch inside screen, while the 80G uses 12-inch diameter outside screen and a 6-inch diameter inside screen. Filling the area between the two screens on these filters with pea gravel or other suitable material provides a means of keeping algae and other marine life out of the pumping system. The extra-large inlet area is said to reduce entrance velocities such that the suction does not pick up foreign matter. Big Foot Manufacturing Co.