The 17-21SYGC/S530-E1/4T is an LED (light emitting diode) manufactured by Everlight. It is a surface-mount device (SMD) LED with a yellow/green color and a water clear lens, with a peak wavelength of 573nm and a luminous intensity of 17 millicandela (mcd). The LED is a standard component and is widely used in a variety of applications, such as automotive lighting, signal indicators, displays, and more.