Pro-Ject Audiophile Head Box S, Black (Box - Head box S Black) Audiophile headphone amplifier provides superior sound quality over typical headphone outputs on integrated amplifiers Front-mounted 1/4 (6.2mm) headphone jack capable of driving headphones with high or low impedance Stereo RCA input and stereo RCA loop output Full metal housing protects against unwanted electrical interference Available with silver or black faceplate