Features Direct replacement for factory 31mm festoon bulb Adds more modern LED appearance Plug and play simple installation Overview Design. The 31mm SMF2 LED bulb is a direct replacement for any 31mm-size bulb commonly found in vanity mirror lights in many vehicles. Populated with two 5050-size SMDs the SMF2 upgrades the factory yellowish incandescent bulb to a more modern LED appearance while adding far more total light output than the factory bulb. The SMF2 was designed with an embedded load resistor and implanted diode for superior reliability. With its durable metal terminals it will fit snugly in the socket and its light weight means it won't vibrate loose over time. Reliability. Unlike other bulbs on the market this bulb is built with constant-current circuitry along with transient suppression. That means this bulb will last for years not months with no flickering or failure. And like every Diode Dynamics product it's backed by an industry-leading three-year replacement warranty. Brightness. With 24 lumens of true measured output the SMF2 LED will provide about double the total light compared to your original 31mm-sized bulb. All Diode Dynamics LED lighting is rated with accurate measured lumen figures not calculations or guesses. We test the true output in-house and provide you the real numbers to compare. Colors. In addition to vibrant colors of blue red amber and green the SMF2 is available in a cool white 6000K and warm white 3000K option as well. Whether you want a modern cool white appearance or a traditional warm white color we have the color to fit your need!