The AKG HP4E is a compact professional 4-channel headphone amplifier AKG used top-shelf components throughout for reliable reference-grade amplification for any pair of headphones even at extremely high volume levels The HP4E offers two stereo inputs and four stereo outputs with convenient switches on the front panel that let you quickly select your desired input Each channel is fitted with both 1/8" and 1/4" headphone outputs for easy connectivity no need for adapters Housed in a rugged metal 1RU half-rackspace chassis the AKG HP4E is a great choice for any recording session