Please note that D1S/D1R/D4S/D4R bulbs include the bulb igniter built in and are designed for replacement applications only. If you are replacing OEM bulbs please keep in mind that OEM bulbs are 4300K/4500K. We strongly recommend replacing all bulbs in pairs in order to keep them matching. We recommend this even when replacing a single burned bulb as HID bulbs tend to change color slightly over time. Our bulbs are rated up to 60w and will work on either a 35w or 55w ballast. Bulbs do not determine the wattage output. All bulbs come with a one (1) year warranty. If the bulbs are purchased with a kit they carry a lifetime warranty as part of the kit.