Presonus HP4 Headphone amplifier

Presonus HP4, 4-Channel Headphone Amplifier, With monitor control, 4 Separately adjustable stereo headphone outputs: 6.3 mm Stereo headphone, Maximum output power: 130 mW per channel, Distortion factor <0.5% THD + N to 60 ohm load, Frequency range: 20 - 20,000 Hz, THD / N: <0.0025% (input and output), Recommended earphone impedance: 32 - 600 ohms, Balanced line input: 6.3 mm jack, L/R, Balanced monitor output for connecting the studio monitor or for looping to additional headphones: 6.3 mm jack, L/R, Monitor level as the main volume controller of the studio monitor, Mute switch for monitor output, Mono switch for headphone outputs, Dimensions: 140 x 140 x 45 mm, Weight: 2.27 kg