Universal output: 3V, 4.5V, 6V, 7.5V, 9V and 12 VDC adapters. Units have four different output connectors: 2.1 mm and 2.5 mm coaxial connectors, 2.5 mm and 3.5 mm mini-plugs, as well as a 9V Battery adapter. Can be used to replace a 9V battery! Polarity reversible. Input: 110V, 60 Hz..