DIY MP3 Player Electronic Learning Kit With Lithium BatteryCircuit diagram here!!!Support FM、 MP3 player、 can be inserted TF card、 USB charging、 digital display. With the main chip CB1090、 RDA5807 is the FM chip、 24C02 is memory chips、  2071 is the amplifier chip. Beautiful sound and powerful.Package included:1 x DIY MP3 Player Electronic Learning Kit With Lithium Battery