Trailer adapter: This adapter allows conversion from Euro 13 - round to American 4 - flat for your trailers, campers, marine caravans and other equipment, allowing you to get a high quality experience . Plug - and - play: The adapter has a plug - and - plug design that minimizes the hassle of internally installing any new wiring and does not require any other adapters. Easy to use. Good stability: The sturdy plastic structure has good stability and is not easy to damage, the brass terminals have excellent conductivity. The housing is made of high-strength ABS plastic, lightweight, wear-resistant, weather-resistant, water-resistant, rust-proof and oxidation-resistant. Secure connection: the adapter can be perfectly compatible with your vehicle, easily clips into the socket and secures firmly without loosening or swinging. The Coil-designed trailer adapter allows the wire not to slip, but allows the trailer to have the extra length required for tight turns, and the extendable coil wire keeps memory and effectively resists bad weather.