These high-quality bulbs are now our choice replacement for OEM Philips and Osram D2 bulbs. With a lifetime warranty backed by both our manufacturer and us, there is no mistake in their performance. Available in 4300k OE color temperature or other pleasing choices of 5000k, 6000k, or 8000k. For use with 50w, 55w, and adjustable output ballasts only. Use with 35w ballasts will result in damage to bulbs.