It’s a standard-sized, 5mm RGB LED, in common-cathode configuration. Tie the long cathode pin to ground, and apply a positive voltage to the individual pins to light up the R/G/B elements in the milky-diffused lens.

The pinout is as follows:

• Pin1 – Red, 2nd longest pin
• Pin2 – Cathode, longest pin
• Pin3 – Green, 3rd longest pin
• Pin4 – Blue, shortest pin

Specifications:

• Milky-diffused lense
• Red element:
  • 630~640nm
  • 1.8-2.0 Vfwd
  • 1000~1200mcd @20mA
• Green element:
  • 515-525nm
  • 3.2-3.4 Vfwd
  • 3000-5000mcd @20mA
• Blue element:
  • 465~475nm
  • 3.2~3.4 Vfwd
  • 2000~3000mcd @20mA