1. Use TM1650 (compatible with AIP650) digital tube driver chip, support 8-level brightness adjustment, working voltage 3.3V ~ 5.5V 2. IIC interface, only need 2 ordinary IO can drive, do not need to repeat scanning of MCU, saving MCU resources. 3. 4 digit 0.56 inch red common negative digital tube with decimal point. 4. 0.56 inch with four 2mm inner diameter positioning holes. 5. Power supply with anti-reverse connection 6. Size 6.0 * 2.2 (cm)