GU10 LED Bulbs are one of the most popular LED Bulbs today. GU10 Bulb is a common type of Spotlight Bulb what you can find in most homes today. It is otherwise known as PAR16 Bulb or GU10 Downlight. They are often used in places where a bright, directional light is needed. The GU10 Bulb has the classic spotlight shape, with a narrow base that widens into a flat or slightly rounded aperture.