Superlux HA3D, Compact headphone amplifier, With 3 headphone outputs, Suitable with in-ear earpieces of up to 20 Ohm, XLR left/right input, Jack loop out, Stereo/Loop in (jack and mini-jack), Battery power: 2 x 1.5 volt or by mains adapter, Suitable for all headphone types, Robust aluminium housing, Frequency range: 10 - 50,000 Hz, Output impedance: 200 Ohm, Dimension: 43 x 94 x 140 mm, Weight: 0.56 kg, Suitable power supply: Art.#233089# (not included)