Description: 1. On-board 2 road 74HC164 serial to parallel chips2. On-board 2 road 0.36 inch red common positive 4 bit 8 segment digital tube3. On-board concatenated control interface, convenient external device to connect4. Working voltage: 5V5. The board size: 35.3 (mm) x29 (mm) Package included: 1 x 8-Bit Serial Interface Red Highlight Digital Tube Display Module