This is 5mm diameter, diffused RGB LED, with common cathode pin. So basically 3 pins are dedicated for Red, Green, Blue light control respectively, while the last pin is the cathode pin for all three color. And since it is common cathode, it will most likely being controlled in active high method. Please do check the datasheet for more details.
- 5mm Tri-color LED
- Super bright
- Colour: RGB (Red, Green, Blue)
- Common Cathode
- 4 pins