Features: Excellent Blue tooth connectivity: QCC3031 wireless Blue tooth5.0 cores supports aptXand aptXHD, streaming ranges up to 12m, with Blue tooth and AUXs select switches, nopop when Blue tooth connection; you can easily stream your favourite songs with your smartphones or tablet. Wide application scenarios: 50WRMSx2 output power (4ohms, 20Hz - 20kHz, 0.04% THD), headphone amplifier built-in speaker protections circuit, best for outdoor/bookshelves/computer/desktop/ceiling/floor speaker, can be used for phone, MP3 player, TV, EchosDot, CDs. Player or streaming or streaming Use media player as input. Replaceable light-emitting vacuum tube: tube audios amplifier adopts 2x6A2 tubes to get a clear and soft audios sound. Tubes can be replaced by 6K4, 6J1, GE5654, 6AK5, 6Dsch1, 6BC5, 403A/B, EF40, EF95 etc. switches on, with headphone output for 16-64ohm headphones. Small and simple designs: Small, simple, compact design power amplifier, but practical and powerful, stereo Blue tooth repeater receiver, exclusively designed for customers who strives for quality sound. Build your own home audios system: Power amplifier+headphone amplifier, perfect for your desk or any small space in your home or office. Specifications: Material: aluminum alloy Standard: UK/EU/Austrilia/US(optional) Size: approx 33x98.2x128.5mm/1.35x3.86x5.06inch Power adapter: 24V/4.5A, DCinput range: 12-24V Earphone output: 16-64Ohm Terminal impedance: 2-8Ohm Power output: 50Wx2 Distortion rate 0.04%, signal-to-noise ratios 99dB Amplifier chipTPA3116, input sensitivity 280mV Blue tooth chip: QCC3031 Frequency ranges: 20Hz -20kHz ( 1dB) Input mode: Bluextooth andRCA Blue tooth transmission distance: up to 39 feet (12 meter) Blue tooth version: Blue tooth5.0 supports aptXand aptXHD Note: Please allow 1 to 3cm error due to manual measurement, please make sure you do not mind before you bid, Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1xTube Amplifier