2.5mm+4.4mm+3.5mm, built-in battery required, HiFi sound quality digital audio decoding module. Built-in USB audio bridge chip and dual-channel low-power high-performance DAC decoding chip, supporting up to PCM384KHz/32bit and DSD256 digital audio codecs, using ultra-low noise power supply and high-precision femtosecond crystal oscillator to further improve performance parameters and sound quality. Integrated 25mm fully balanced differential output/4.4mm fully balanced differential output/3.5mm stereo output, the load supports 16ohm-600ohm output two-level gain switch control, and can be perfectly adapted to all types of headphones. The built-in carp battery design can completely solve the problem of quality degradation caused by the interruption of overload work of the HiFi decoder caused by the current limitation of the for interface of the mobile phone and the insufficient power supply, and truly realize the HIFI music presentation of the mobile phone. It also provides a built-in battery and mobile phone power supply switch. Android phone users can flexibly choose to use the battery or mobile phone for power supply to obtain better battery life . Excellent device compatibility, it has been to support the HiFi music listening function of mainstream smart terminals such as for , for , for , for , for , for , and for . Speaker impedance:32ohm Drive voltage:2000mV (125mw); 1000mV (31.25) Distortion:-103dB-100dB Signal-to-noise ratio:125dB-120dB Dynamic range:125dB-120dB Crosstalk:-120dB-60dB Colour:Black Material:Plastic+Metal Package Contents: 1 * audio module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.