Specifications:Built-in 2200mAh battery can be used for 10 days.Portable voice amplifier is designed with large volume and clear sound, and there is no noise.It is suitable for teaching, tour guides, parties, lectures, promotions, training, etc.How to use the microphone: When you press and hold the power button, the blue indicator light will light up. Insert the 3.5 plug of the microphone into the corresponding microphone jack of the amplifier, and adjust the volume to achieve the desired sound amplification effect. Special Reminder: In order to achieve normal volume, when wearing the microphone, please aim the direction of the microphone toward your mouth and keep the closest distance.Music Mode:Power on and insert the TF card to play music in the card, and the power light flashes.Previous Song Button: Short press: Previous Song. Long Press: Single CyclePlay/Pause Button: Short Press: Play/Pause. Long Press: Turn On/OffNext Song: Next SongWhen the host is charged and used under low voltage: When the voltage is too low, the blue light of the power indicator flashes, indicating that the battery is insufficient, but it can still be used. Please charge the host in time. When the voltage is too low, it will automatically shut down. The charging time is about 4 hours. The indicator light will be red when charging, and the indicator light will go out when fully charged.Item Name: Audio SpeakerMaterial: ABSBattery: Built-in 2200mAh Battery (Included)Maximum Power: 8WDistortion: less than 0.5%Frequency: 50Hz - 10KHzOutput Resistance: 2 ohmWork Temperature: 10 Degree Celsius - 45 Degree CelsiusWorking Voltage: 3.7VCharging Time: about 4 - 5HFeatures: Wired Microphone, Teaching Accessory, No NoiseSize: 8.4cm x 9cm x 2.8cm/3.31" x 3.54" x 1.10" (Approx.)Notes:Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Audio Speaker1 x User Manual1 x USB Cable1 x Wired Microphone1 x Lanyard