A CFL bulb, or compact fluorescent lamp, is an energy-efficient lighting option that uses a gas-filled tube to produce light. When electricity flows through the gas, it emits ultraviolet light, which then excites a phosphor coating inside the bulb, creating visible light. CFL bulbs consume about 70% less energy than traditional incandescent bulbs and can last up to ten times longer. CFL bulbs are available in various shapes and sizes, making them suitable for different fixtures. They are often used in homes and businesses to reduce electricity costs and lower environmental impact. However, they contain a small amount of mercury, so proper disposal is essential.