Unlike other bulbs, to install an H7 LED bulb, you have to remove the collar/ring before locking the bulb into the place.Here are the steps:Twist the collar on the bulb until it loosensPlace the collar onto the liight housingSecure the factory spring/clip over the collarReinsert the bulb through the secured collar and twist into place.The above installation steps can be applied to most vehicles. However, for many Volkswagen/Mercedes Benz/Hyundai vehicles, the bulbs are held in place with an extra adapter. Please check here to see different adapters/retainers.This is a metal adapter on Volkswagen Jetta 2012The stock adapter can’t work with the LED bulb, so to swap your halogen bulb to LED, you’ll need an aftermarket adapter.Here is the adapter for Volkswagen Jetta 2012, and the product link in case you’re interested in.Also, LASFIT designed a custom LED bulb LAG1, which is specially used for this vehicle. With this LED bulb, you no need an additional adapter, just plug and play, as your factory bulb did.Actually, there are so many different adapters for H7, if your factory halogen bulb H7 also comes with an adapter, and it is not the same as the above one, please contact us to get professional support before placing your order.