ATTENTION: THIS PRODUCT IS BEING SOLD AT A DISCOUNT BECAUSE IT IS NOT BRAND NEW. IT MAY BE AN OPEN BOX RETURN, MAY SHOW SIGNS OF INSTALLATION OR USE, AND MAY HAVE OTHER IMPERFECTIONS OR BLEMISHES THAT SET IT APART FROM A FULL-PRICED PRODUCT. THE WARRANTY DIFFERS FROM THAT OF A BRAND-NEW SET. PLEASE COMPARE THE DETAILS OUTLINED IN THE 'WHAT'S INCLUDED' SECTION BELOW WHEN ADDING TO YOUR SHOPPING CART.

Features: Low or high beam LED headlight replacement. Correct optical focus for increased output with no added glare. Perfect H10, no modification needed. Designed and validated to OEM lighting standards. Engineered and Assembled in USA.

Aftermarket or OEM?: If you're looking to improve visibility on your vehicle at night, you've probably found many options for LED upgrades. Most bulbs on the market are too big to install, don't work with the electrical system, and have no focus or hotspot in the beam pattern. Even if they come close on those aspects, they still aren't anything close to the quality you would find with factory-installed lighting. Like most aftermarket products, most LED bulbs are not engineered and tested for long-term reliability.

With the SL1 LED: Diode Dynamics set out to engineer a true OEM-grade solution. With its compact size, optically correct output, flow-simulated cooling, and boost-mode electrical circuit, our SL1 LED patented design is a properly-engineered solution that finally provides a true upgrade in performance, with high reliability: and it's tested and validated to meet those standards, just like OEM lighting.

Compact Size: Your order includes two bulbs, to replace the factory bulbs in your vehicle. The bulbs are compact in size, in a patented design that isn't much bigger than the original halogen bulb. The drivers are compact too! If you have a sealed headlamp, they are designed to fit inside. The drivers and bulbs are tested to last over time, even when sealed inside with the heat of the headlamp. Please note that if you are replacing a high beam / DRL bulb, the DRL function may no longer work, depending on your vehicle.

Street Legal Output: Don't be fooled by high lumen numbers or "projector specific" bulbs. Your vehicle's headlights are designed as a system, to focus light. If the light source in that system is out of focus, it doesn't matter how bright it is. You won't have a focused hotspot of light to shine down the road, you'll just have more glare. To correct this, the SL1 LED headlight bulb was engineered with advanced optical design software, which simulates each ray of light in a process known as "ray tracing." Using this tool, our engineers perfectly matched the filament location, allowing the SL1 LED to focus light just like your original bulb, preserving the focus and hotspot, with no added glare. It produces a functional pattern on the road, with a stronger hotspot for added distance. This is a safe, functional output, in compliance with photometric standards, which we call Street Legal.

Daytime Running Light: Daytime Running Lights (DRLs) are lights that illuminate when the vehicle is running, and when all other lights are turned off. Some vehicles use the high beam bulb as the daytime running light. If your vehicle uses voltage drop for the DRL signal, the SL1 will operate at full brightness. If your vehicle uses PWM for the DRL signal, the SL1 will operate at a reduced brightness level just like your factory halogen bulb would.

Tested to Perform: We test the SL1 bulb in factory headlamps, and measure the entire beam pattern using specialized equipment. It's an elaborate affair: a headlight is mounted to a computer-controlled rotating head called a goniometer. Light shines down a tunnel, where a sensor collects data as the headlight is rotated. The entire beam pattern is mapped, and we compare the total output to the original halogen, confirming that the SL1 bulb shines more light in the hotspot, without adding extra glare on the road. The test results speak for themselves: in most lamps, like the 2015 F-150 Halogen lamp, there is 30-70% more light in the critical hotspot, with no added glare or spread of light. With proper optical engineering, testing, and validation in the application, we can assure correct optical performance.

Staying Cool: You may have seen bulbs that use large straps for cooling, or big fans that just make noise. These bulbs still run hot, pushing the LEDs past their limits, resulting in degradation of output after a few months. When it comes to cooling, proper engineering is required to efficiently remove heat from the bulb. In the SL1, it comes together as a whole system that was extensively tested, with dozens of iterations to achieve the best cooling performance possible. It includes a direct-solder copper core board, thermal phase-change interface material, and thermally-modeled zinc casting get heat to the base, where base fins are designed for aerodynamic performance in conjunction with the flow rate and pressure of the Sunon bearingless microfan. The result is a highly-effective and reliable cooling system, keeping the bulb running at maximum potential.

Fitment: With its patented design, the SL1 LED fits where other bulbs won't, without cutting or modification. There's no hanging metal straps, just a compact bulb that plugs right in, with an exclusive reinforced shroud to keep the heat off any other components or wiring. Only slightly larger than a standard halogen bulb, it fits behind dust caps and in tight spaces. The driver and bulb are tested to function when sealed inside the headlamp - no worries about heat buildup! The base sizes on the bulb are also are keyed for exact applications, not one-size-fits-all, and the compact driver easily tucks away.

Driven: Rather than a simple buck regulator found on other bulbs, the SL1 uses a unique boost-mode circuit, which prevents thermal imbalance in the LEDs over time - again, just like you would find in OEM LEDs. It also has transient protection for long life in automotive circuits. Diode Dynamics engineers also analyzed dozens of OEM electrical systems, and added current-monitoring circuitry to mimic the electrical characteristic of halogen bulbs, drastically reducing the need for CAN-BUS adapters (though they're still needed on some applications).

Reliability: Every part of the SL1 LED was designed for reliability, from the custom wiring with strain reliefs and solderless terminals, to the exclusive zinc castings, to the reinforced high-temperature PP-GF plastics (the same used in halogen bulb bases). Each component was designed and tested, with dozens of variations of each component reviewed until we achieved the maximum performance possible. Finally, the SL1 was put through its paces in our environmental testing chambers - where the bulb successfully performed through dozens of thermal cycles, from -40 through 85 degrees Celsius (-40 to 185F). Whether you're in the Sahara or northern Canada, the SL1 will keep performing for years.