This paper discusses the design, fabrication and testing of a double side impingement air-to-air heat exchanger for cooling of electronic cabinets. Operating principles and advantages of the new heat exchanger concept are discussed, which is followed by descriptions of a theoretical model that can be used to predict the heat exchanger thermal performance. Prototype heat exchanger test results are compared to validate the theoretical model predictions. In addition to thermal tests, environmental tests were also conducted to qualify the heat exchanger for outdoor applications. Procedures of selecting impingement heat exchangers for specific applications are presented at the conclusion of the paper.