Features: Power supply voltages: 5V (ranges 3.7-5.5V, support 3.7V/4.2V such as 18650, output capacity>200mah) Power supply current: 300ma (>50ma is also acceptable when the speaker is not connecting) Standbys current: 36MA Working current: >50MA (specifically related to the speaker and sound size) Triggers port: 19 (one port corresponds to one MP3) Function port: 5 (up and down music, volumes increase and decrease, pause/play) Possible modes: single without loopings, single loopings, playback without interruption, long presses play modes Speaker parameters: 0.5-5watts 2-8ohms (volumes adjustable) File format requirements: You need to create a folder named "01" and then save the files 001.MP3 -019.MP3 Note: When using battery power supply, make sure the capacitors capacity is large enough, otherwise it will not work properly after the voltages drops to 3.5V when there is a lack of power. Specifications: Component:Plastic Size:Approx.72x35mm/2.83x1.37inch Model: M3D5T Working temperature and humidity: -20-50, HR5%-90% Supported playback formats: MP3, WAV Maximums memory supported: 32G Package Includes: 1pc Voice Playback Module note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual item color.