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 do not solder VCC-VDD pad, the PCF8575 level is 3.3V. If you solder it, the level will be the same with VCC.

Features:
Size: 4x2.1cm/1.57x0.83inch
available library: PCF8575
Working voltage: 2.5 - 5.5V DC
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 UNO R3 and other MCU to control simple relay, buzzer, button, led.

Package included:
4pcs PCF8575 IO Expander Board Module I2C to 16IO