The INTEGRA III SYSTEMS Limiter/Line Amplifiers are designed for professional audio applications. There are six different models, 3 single channel models, and 3 dual channel models. Dual channel cards have two identical channels constructed on one printed circuit board assembly. The INTEGRA III SYSTEM Limiter/Line Amplifiers offer four different models, 2 single channel versions, and 2 dual channel versions. The input section of the line amplifiers is available in two different impedances. They are; 10K ohm balanced, transformer-isolated, and 600 ohm balanced, transformerisolated. This allows the user to match the line amplifiers to a variety of professional audio equipment.