Amazon.com: Neewer Super Compact 4-Channel Stereo Headphone Amplifier with DC 12V Power Adapter for Sound Reinforcement, Studio, Stage, Choir, Personal Recording, Features Ultra Low Noise (Original Version) : Musical Instruments
Behringer HA400 4-Channel Headphone Amplifier - Black for sale online | eBay
Behringer | Product | HA400
Amazon.com: On-Stage HA4000 4-Channel Pro Headphone Amplifier,Black,White : Electronics