HID Bulb Base Lock Adapters

These adapters are usually needed when upgrading from H7 halogen bulbs to H7 HID bulbs, and the vehicle has it's own proprietary way of locking the H7 halogen bulb in the headlight. You'll need to match the adapter to the one that is specific to your vehicle's manufacturer (VW, Mazda, KIA, etc), in order for the HID bulbs to lock in headlight. The slot in the adapter is there so you can run the HID bulb's positive and negative wires through it.