Vistreck Ultra-compact 4-channel Stereo Headphone Amplifier Upgraded Mini Audio Amp with Mono & Stereo Switch Power Adapter Professional Mono/Stereo Audio Amp for Studio and Stage - Walmart.com
Rolls HA43PRO - Amplifiers
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