Dual LED is a backlight technology where a TV uses two different color temperature LEDs—usually warm (yellowish) and cool (bluish).
By switching or mixing these two, the TV produces better contrast and more accurate colors compared to a single white LED backlight.
For example, when watching a sunset scene, the warm LEDs enhance orange and red tones, while cool LEDs help in bright daylight scenes.
See also: Backlight, Contrast Ratio, Local Dimming