The G4 halogen is one of the most common lamps used in caravans and motorhomes and is easily identified as a small glass lamp with two short pins spaced 4mm apart. The G4 halogen is commonly used in ceiling lights, wall lights, downlights and reading lights and is easily replaced with an LED alternative. This disc type LED G4 is used to provide light in one direction and are best used in downlighters, ceiling lights and spotlights. The 21-LED back pin is our brightest back pin G4 LED. This G4 sits straight back in the light fitting. We also have this 21-LED G4 as a side pin version and have smaller versions too if a different light output is required.