1. The display device is a 4-digit common positive red digital tube. 2. The 8-level gray scale of the digital tube is adjustable. 3. The control interface level can be 5V or 3.3V. 4. Four M2 screw positioning holes for easy installation. 5. Control interface: 4 pins in total (GND, VCC, , CLK), GND is ground VCC is the power supply, is the data input and output pin, and CLK is the clock signal pin. Digital tube: 4-digit 0.36-inch digital tube with common anode and score points, with red letters highlighted. Positioning holes: 4 M2 screw positioning holes with a diameter of 2.2MM, making the module easy to install and position. bit to achieve combination between modules. size: 4.2 x 2.4x 1.2cm Material: plastic colour: Blue Package Contents: 1 x module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.