The module is based on a 4 digital tube (0.56 inches) which can display the clock point. The decimal point is not displayed and the driver chip is TM1637. Simply two signal lines can make MCU control 4-digit 7-segment LED. It can be used to display the integer clock stopwatch score and so on. The features are as follows: 1.Compatible with Arduino UNO MEGA2560 Leonardo; 2.4 digit red alpha-numeric display with clock point; 3. 8 adjustable gray; 4. Power Supply should be 3.3~5.5V DC; 5. Logic level of the interface can be 3.3V / 5V; 6. 4 screw mounting holes whose diameter is 2.2mm;