The Heco OL-340 is a low-frequency loudspeaker chassis that was manufactured between 1972 and 1974 in Germany. It is part of the Heco OL series, which includes several other models such as the OL-300, OL-410, and OL-600. This loudspeaker is designed for orchestral audio applications, likely providing significant depth and clarity suited for reproducing lower frequencies. The specifications and features of the OL-340 may include various dimensions, power handling capabilities, and frequency response characteristics typical of the era's audio equipment, but specific technical details are not provided here.