Energy Recovery, Inc. is engaged in developing, manufacturing and selling energy recovery devices for selling in the seawater desalination. The subsidiaries of the Company include Osmotic Power, Inc., Energy Recovery, Inc. International, and Energy Recovery Iberia, S.L. There are two methods of producing drinking water from seawater: thermal distillation and membrane or reverse osmosis desalination. Thermal distillation involves heating seawater, capturing the vapor and condensing it as potable water. Reverse osmosis desalination entails pressurizing seawater and driving it into filtering membranes to produce pure water and concentrated brine, which is carried away in a high pressure reject stream. The energy recovery products are used in reverse osmosis desalination. The products of the Company are sold under the trademarks ERI, PX, Pressure Exchanger and PX Pressure Exchanger. In December 2009, the Company acquired Pump Engineering, L.L.C.