Philips Diamond Vision bulbs are a styling product for motorists looking for a bulb that will stand out from the crowd. Philips Diamond Vision produce a distinctive blue look in the headlight due to their colour temperature of 5000K. If you are looking for greater light output, then this isnt the choice for you as this product is specifically designed for styling and they are not road legal within the EU. You should choose Diamond Vision if you are looking for a distinctive blue light on the road to enhance the styling of the vehicle.The standard unit for colour temperature is Kelvin (K). Brightness is measured in lumen. Standard halogen bulbs produce yellow light at 3200K. Xenon HID technology produces white light at 4200K. The colour temperature for bluish white light is 5000K. The colour and brightness of the headlights in the visual is not an actual representation of these Philips headlights.Are they legal to use and do I need to modify my vehicle? Diamond Vision can be used without making any changes or modifications to your vehicle. They just need to be exchanged with the bulbs that you are currently using. This product is not road legal within the EU. Philips Diamond Vision car bulbs do not comply with ECE R37 regulations and are not road legal. We are therefore not legally responsible for any future action relating to the use of these non-road legal bulbs if used on public highways or any other on-road situation.