Descriptions: Have you run out of I/O pins? This great module allows the user to expand up to 16 I/O using only two I/O for control! The PCF8575 is controlled through an I2C interface and features 16-bits of quasi-bidirectional input/output pins. On board 3.3V level converter circuit, if you donot solder VCC-VDD pad, the PCF8575 level is 3.3V. If you solder it, the level will be the same with VCC Features: Available library: PCF8575 Working voltage: 2.5 - 5.5VDC Working current: 100mA(MAX) I2C address: 0x20(default),can be modified by soldering A1 and A2 selection pads. 16 individually addressable pins. Each pin configurable for input or output Open-drain interrupt output pin for input change interrupt. Great for other MCU to control simple relay, buzzer, button, led. Size: 4x2.1cm/1.57x0.83inch Quantity: 1 Pc Note: Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 Pc x Expander Module