Features: 1. The signal light adopts a mixed color of red, yellow, blue, and green, with rich and eye-catching colors. 2. Adopting plug-in/patch technology to meet different welding requirements. 3. Support low-level triggering, simplify circuit design and connection. 4. Built in current limiting resistor to protect the LED and extend its service life. 5. Wide application range, DC3.3~5V is suitable for various control platforms. Parameter: Product Name: Four digit LED Module Material: Double layer PCB board, thickness 1.6mm Working voltage: DC3.3~5V Signal light color: red, yellow, blue, green mixed color PCB board size: 19mmx65mm Process: Plug in/SMT Signal light size: 10mm Interface description: VCC is connected to the positive pole of the power supply, and D1, D2, D3, and D4 are connected to the IO pins of the controller Input method: Low level (or ground) signal, LED lights up Installation holes: 4 fixed installation screw holes with a diameter of 3mm Current limiting resistor: Yes Power indicator light: none Work platform: microcontroller, ARM, etc. Package Include: 1X module