Phantom YoYo Arduino Compatible Joystick Shields Rocker Button Extended Board PS2 game rocker (X axis A0, A1 Y axis and Z axis keys D6) Four independent buttons (D2, D3, D4, D5) Reserved extended interface:an I2C interface,a TTL serial port. Analog interface (A2 - A5),Digital interface (D8 - D13).Arduino reset button. NOTE: the reserved extended interface need to welding pins yourself.