The Shure A95U is a reversible transformer that matches low- or high-impedance microphones to high- or low-impedance inputs. The transformer permits use of very long microphone cables with high-impedance microphones. However, when connecting a high-impedance microphone, limit the cable length between the microphone and the transformer to 4.6 m (15 foot). The cable from the transformer to the low-impedance input can be any desired length.