Retekess TR619W Portable Amplifier Digital FM Radio Player with USB TF Card Socket AUX In and Wireless Microphone Voice Amplifiers Rechargeable for Classroom Meetings Outdoors

Features:
Multi-function, can be used for power supply but can be rechargeable when it's out of power.
Built in high-capacity lithium battery enables it to give you an ultra long playback.
When connected to a computer, it can be read via USB / TF card socket.
One-click recording, can record external audio, microphone
Not only a voice amplifier, but also an FM radio.
Supports MP3 audio format.