You can use a jumper cap to select VCCIO to connect to a voltage of 5V or 3.3V (VCCIO can be used to power the VCC pin connected to the board) Power Indicator:Module power indicator light for easy viewing of module power supply status interface:Connect to the interface corresponding to the microcontroller FT245BL:USB independent chip for parallel FIFO bidirectional data transmission interface. Complete USB protocol processing chip - no need for specific USB firmware programming USB to FIFO, MCU communicates with PC. USB interface: Provide mini USB interface VCCIO power supply jumper Colour:As Shown Material:plastic Package Contents: 3 x FT245 module 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.