Mic 2U HA400 Ultra-Compact Audio Amplifier 4 Channels Mini Stereo Headphone Amplifier With Power Adapter sound amplifier
Behringer HA400 - YouTube
HA400 Ultra-compact 4-Channel Mini Audio Stereo Headphone Amplifier US Plug P0I0 | eBay
Behringer HA400 – Thomann France
HAYDEN HA400 Headphone Amplifier 4 Ch Channel Metal Stereo Audio Amplifier, Mini Earphone Splitter with Power Adapter - 4X Quarter Inch Balanced TRS Headphones Output and TRS Audio Input for Sound Mixer :