The 551-3513F is a 3 mm common cathode dual-color LED indicator manufactured by Dialight, featuring integrated green and red light-emitting diodes with three leads (green anode, common cathode, red anode). The device delivers radiant intensity of 29–100 mcd at 20 mA forward current, with peak emission wavelengths of 565 nm (green) and 630 nm (red), and a viewing angle of 75 degrees. Operating specifications include a maximum DC forward current of 30 mA, peak forward current of 90 mA (duty cycle <1/10, pulse width <10 ms), and power dissipation of 78 mW, with forward voltage ranging from 2.0 V to 2.6 V at 20 mA. The device operates reliably across a temperature range of -30°C to +85°C, with storage capability from -40°C to +100°C, making it suitable for status indication, alarm signaling, and multi-state visual feedback applications in industrial and consumer electronics.