Simply Auto Headlight Bulbs - H4

Yes, the quartz glass construction is designed to resist thermal shock and adverse weather conditions, ensuring durability and performance in various environments.

'E-marked' signifies that the bulbs comply with European safety standards and regulations, making them road legal for use on public roads in many regions.

You can typically find this information in your vehicle's owner's manual. Alternatively, you can check the existing bulb or consult a mechanic or auto parts specialist.

No, these are standard halogen replacement bulbs and are not compatible with LED or HID conversion kits. They are designed to function as direct replacements for existing H4 halogen bulbs.

The UV filter in the quartz glass helps protect your headlight lenses from UV radiation damage, preventing them from becoming yellowed or hazy over time and maintaining optimal light clarity.

While lifespan can vary based on driving conditions and usage, these bulbs are manufactured for high performance and long-lasting quality, intended to exceed the lifespan of standard, lower-quality halogen bulbs.

It is generally recommended to replace headlight bulbs in pairs. This ensures consistent light output and brightness between both headlights, and if one bulb has failed, the other is likely nearing the end of its lifespan as well.

Ensure the bulb is correctly seated in the socket and the retaining clip is secure. Check the vehicle's fuse for the headlights. Verify the vehicle's electrical system is functioning correctly. If problems persist, the issue may lie with the vehicle's wiring or switch.

Ensure the bulb was not handled with bare hands during installation, as oils can cause premature failure. Verify the vehicle's voltage regulator is functioning correctly, as over-voltage can shorten bulb life. Check for excessive vibration which can also damage filaments.

Confirm the bulb is installed at the correct angle and orientation. Ensure the headlight lens is clean and free from damage or hazing. Check for proper alignment of the headlight assembly.