Manufacturer Model Variant Year Reset Manufacturer Model Year Manufacturer Model Year

Definitions Page

This page has some definitions for some of the abbreviations and terms used on this site and regarding automotive lighting in general.

284, 343, 380, 381, 382, 501, 566, 580, 581, 582

Some of the most common fitting types for indicator, rear and brake bulbs. Also occasionally used for internal lighting.

Aftermarket

Usually used to refer to something added to a vehicle that was not factory fitted, such as adding more powerful lights or an in-car DVD player.

Angel Eye

Common on BMWs, and now appearing on Audi and some other cars, this is a ring or strip of lights around the main headlight. Normally LEDs, they are generally used as daytime running lights (DRLs)

Beam Blades

A new type of windscreen wiper blade that does not use the traditional metal frame, but instead had a single flat beam with a metal core. They are flatter than traditional blades, and once adjusted correctly give a more even pressure on the screen. Fitted as standard to some new vehicles, they are available as aftermarket upgrades for most vehicles.

Crystal Lights

A style of light units with very clear lenses. Pioneered by Lexus and other top end models, they are now available on many makes of vehicles. These type of fittings means that the bulbs and reflectors are generally on show. Silver coated bulbs give a better look with crystal indicator fittings.

D1S, D1R, D2S, D2R, D3S, D3R, D4S, D4R

The most common fitting types for factory fitted Xenon HID headlight bulbs.

DRLs

DRLs (Daytime Running Lights/Lamps) are lights used to make a vehicle more visible in the daytime. They are often tied to the ignition and cannot be turned off. They are common on older Volvo cars, motorcycles, and will be required on all new vehicles in the UK from 2012. To save power, many DRLs on newer cars use LED lighting.

Filament

A piece of metal inside a lamp that conducts electricity and gives out light. Usually made from temperature resistant metals like Tungsten, the exact metals and the gas they are in is selected for the brightness and colour of light required.

H1, H2, H3, H4, H6, H7, H11, H13, HB1, HB3, HB4

The most common fitting types for traditional filament headlight bulbs, these are the 'standard' references, but some manufacturers use their own references as well.

Halogen

Halogen is a class of gasses used in lamps to prevent the filament burning under the heat it generates, and to extend it's life.

HID

HID stands for High Intensity Discharge, where the light in a bulb (technically called a lamp) is generated by an arc of electricity between the two electrodes. The special gas inside the HID lamp makes the arc of electricity much brighter than it would otherwise be. HID lamps are far more efficient than traditional filament bulbs, giving much more light for the same amount of power.

Kelvin

A rating of the colour temperature of a bulb, giving an indication of the visible colour.

• Standard Halogen: 3000k (Yellow)
• Factory Fitted HID: 4300K (Yellow White)
• Upgrade HID: 5000K (Pure White)
• Upgrade HID: 6000K (White with Blue Tint)
• Upgrade HID: 8000K (Blue)

Higher colour temperatures go though blue to purple and outside the visible spectrum.

Lamp

Technically, a lightbulb is called a lamp by engineers. Generally, we use the terms lamp, bulb and lightbulb interchangeably.

LCD

A Liquid Crystal Display uses liquid crystals and a polarised screen to create a display. Some aftermarket car products, such as parking sensors, use LCD displays to provide information to the driver.

LED

A LED (Light Emitting Diode) is a small lamp that generates light directly from electricity, creating a very efficient light with very little heat output. Not quite bright enough for headlights, they are used for tail lights, brake lights and indicators, as well as internal lighting. Their small size and low power use makes them great for add-on lights internally and externally. LEDs can be designed to output a variety of colours.

OEM

Original Equipment Manufacturer means that this is the same make as the equipment originally fitted to your vehicle in the factory. OEM products are often more expensive, but are guaranteed to be compatible.

Projector Headlights

Form of headlight designed to give a more tightly focussed light with a longer range. In these type of headlights the bulb is hidden behind a lens that focusses the light, so it cannot be seen.

Reflector

A type of headlight fitting where the light is bounced off one of more mirrored components inside the headlight fitting. Designed to give better light distribution without causing glare on modern vehicle,. Generally, a specific lamp is required for refelector type headlights.

TFT

TFT stands for Thin Film Transistor, a type of LCD screen. It's designed to give a sharp picture on a slim screen.

Tungsten

Tungsten is a metal commonly used in bulb filaments. It has a very high melting point, and is also used for things like welder tips and rocket engine nozzles

Wedge lamp

Type of bulb that uses a the body of the bulb itself to slot into the holder, usually used for tail and indicator bulbs as they are pretty small.

Xenon

Xenon is a gas that naturally occurs in very small quantities. It is used in both traditional filament bulbs and HID lamps. In both types of bulbs it is used as it is very inert, preventing the internal components of the bulb burning in the heat they generate. 'Xenon Lamps' use a traditional metal filament surrounded in Xenon gas to prevent it burning. 'Xenon HID' bulbs use a arc of electricity inside a bulb filled with a mix of gases and metal salts including xenon.