Have you ever wondered why light bulbs, which are referred to as LAMPS in the National Electrical Code are classified the way they are? With entire aisles in home improvement stores devoted to this humble product, the seemingly endless options can feel overwhelming. What exactly do labels such as A19, G25, and T12 mean? The system for identifying bulbs is actually simple, straightforward and consistent. Once you learn a few basics, you’ll be able to see bulbs in a whole new light!