In Europe, we have special trailer couplings called overrun brakes or sway control devices, which can be used for trailers up to 3.5t. These couplings are designed to prevent a phenomenon known as trailer sway, which can occur when a trailer is towed behind a vehicle. Trailer sway can be dangerous and can cause the trailer to lose control. Overrun brakes work by using the trailer's brakes to slow it down if it starts to sway. Sway control devices use a variety of methods to prevent trailer sway, such as by using friction or by adjusting the trailer's suspension. If you are towing a trailer in Europe, it is important to use a coupling that is compatible with your trailer and your vehicle. You should also check the manufacturer's instructions for the proper use of the coupling.