OEM hands-free kits are installed in the vehicle completely hidden. They are usually installed in the dashboard of the vehicle and connected to the original car radio. These OEM hands-free kits usually behave similarly to the original kits and can in most cases be controlled with the original buttons on the steering wheel or under the steering wheel. A large part of these OEM hands-free kits also have other inputs, for example for iPod or USB input. Before buying, you need to check whether your original car radio has a CD changer input. When making a phone call, you need to switch to media or CD changer, then you can make a call via the OEM hands-free kit. Most hands-free kits also come with an external microphone, which must be installed in the car.