A truck, commonly referred to as a freight car or a truck, is a vehicle used primarily for transporting goods, and sometimes for towing other vehicles. It belongs to the category of commercial vehicles.Most of the truck can be done using the trailer, divided into semi-trailer and full-trailer, trailers are used widely in our lives, when the truck is using as the trailer , they usually need to add trailer parts to connect to the vehicle, different trucks have different trailer parts, but the difference is not big. This article mainly introduces what are the trailer parts.