Features: Adopts SC16IS752 + SP3232 dual chip combination, converts SPI to RS232, data rate up to 921600bps. Breakout SPI control pins, for connecting with host control boards. Comes with development resources and manual (examples in C and Python). Onboard LEDs for indicating the power and transceiver status. Onboard TVS (Transient Voltage Suppressor), effectively suppress surge voltage and transient spike voltage in the circuit, lightning-proof & anti-electrostatic. Standard Raspberry Pi 40PIN GPIO extension header, supports Raspberry Pi series boards. Specifications: UART expansion chip: SC16IS752 RS232 transceiver: SP3232 Communication interface: SPI Data rate: 300 ~ 921600 bps Operating voltage: 3.3V/5V Dimensions: approx. 65x56.5mm/2.56x2.22in Mounting hole: 3.0mm Note: No retail package. Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1PC x 2 Channel Isolated RS232 Expansion Hat