Do I need the bulb for this headlight?

This assembly comes as a housing only—no bulb included. Check your vehicle's service manual or existing headlight for the correct bulb type and wattage, then source separately.

Will this work if only one headlight is damaged?

Yes. This is a single left-side assembly, so you can replace just the broken side. The factory design matches both sides, so a one-side replacement will look correct.

Do I need new gaskets or sealant when installing this?

Mounting method varies by installation approach. If you're bolting it directly to existing brackets, reuse your current gaskets or purchase fresh ones based on your vehicle's design. Test-fit first to confirm what you need.