Lumens and candela are the most common terms you will see a manufacturer use when marketing their pistol lights. Lumens refers to the raw measurement that describes how much light the LED can theoretically produce. Candela, on the other hand, describes the total amount of light within a certain beam angle and direction and helps measure the strength, volume, and intensity of light. Candela is a much better predictor of how the light is going to perform, especially for products like the Surefire X300 Turbo and Modlite PL350, which are both designed to produce a beam that reaches out to longer ranges.