FeaturesBrighter, cool white LED outputDirect replacement compatible with GMC Sierra 3500 reverse light bulbPlug and play, no modification with factory 921 bulb sizeImproved visibility behind vehicleAvailable in multiple brightness levelsOverviewBrighter Backup. These replacement LED bulbs are a great way to improve the look and function of the reverse lights on your vehicle. You will get higher visibility at night, with a modern look. The installation is straightforward, with just a bulb swap - making this one of the easiest ways to improve your vehicleâ€s lighting.Brightness. 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 that match. At Diode Dynamics, we test each batch of products to ensure that all bulbs will match in color, and avoid various tints of white. These bulbs will match any other upgrades you may have from Diode Dynamics, for factory-style uniformity and a clean appearance.Reliability. Diode Dynamics LEDs are built with constant-current inductive circuitry, along with transient suppression. While more expensive than simple bulbs, this allows Diode Dynamics LEDs to last for years, with no flickering or failure.Experience. After over a decade in business, Diode Dynamics is one of the most trusted names in automotive LED lighting. We directly assemble and engineer our own products in the United States, allowing for higher quality and performance, with the newest and brightest LED technology. We pride ourselves in offering only the best possible LED solutions.