CRT displays, or cathode ray tube displays, are a type of screen technology that was widely used in televisions and computer monitors before the advent of flat-panel displays. They work by firing electrons from a cathode through a vacuum tube onto a phosphorescent screen, creating images by illuminating specific areas. These displays are known for their deep colors and high refresh rates, making them popular for gaming and graphic design in their time. However, they are bulky and heavy compared to modern technologies like LCD and LED displays, which have largely replaced them due to their slim profiles and energy efficiency.