Expansion Board provides jitter- audio with 112dB DNR audio quality, built-in high-quality Class D stereo audio amplifier(TI TPA3118D2); use theoriginal ALPS RK163 series potentiometer for smoothly volume adjustment. When you use it, Under 24VDC conditions, up to 2 x 30W input and 8OBTL load, it can drive 4 speakers, also suitable for high impedance speakers. Expansion Board uses technology advanced stereo DAC ES9023, full HD audioup to 24bit/192kHz playback. Expansion Board Onboard pluggable speaker screw terminal, XH2.54 connector, provide 5V output for other devices. Uses the digital I2S audio signals to reduce CPU load over USB audio solutions; -noise can be improved by enabling GPIO control; AMP can be enabled / disabled with jumper link. Specification: Power Supply: 6-26V DC, recommended 3A Use GPIO: LRCK-IO19, BCK-IO18, DATA-IO21, IR-IO26, AMP mute-IO22 RCA Analog Audio Output Level: 2V RMS Amplifier Maximum Output Power: 2x30W (4 line load at 24VDC) Resolution/sampling Rate: Up to 24bit/192KHz (for I2S) Scope of Application: For 1 Model B+/ 2 Model B / 3 Model B / 3 Model B+ / 4 Model B Instructions for use link:raspberrypiwiki.com/X5500 Note: Not include for Board; Don' your for via the Pi's 40-pin header and Type-C or Micro-USB socket at the same time; Application: Compatible with X710 for intelligent power and cooling your amplifier (See notes1) Compatible with X850 for mSATA SSD storage expansion (See notes 2) Compatible with X872 for M.2 NVME SSD storage expansion (See notes2) Compatible with X860 for M.2 SATA SSD storage expansion (See notes2) : Moode Audio Player OSMC Openelec Raspbian Volumio Pi Core Player note: Different batches may have different appearance, which does not affect use. Colour: Black material: PCB+electronic components+metal Package Contents: 1 * X5500 Expansion Board 1 * screw pack 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.