Patented, automatically technic as well as an optimal and secure power transfer for an easily manoeuvring of caravans and trailers (single axle). Large engaging way and innovative driving roller surface for a safe manoeuvring and a small turning circle. Less weight because of the special mix of materials. The particular engage mechanism with high-performance plain bearings makes the coupling easy at a minimum loss of ground clearance. Technical details: Automatical one-hand operation, climbing power 15% at 1.800 kg respectively 30 % at 1.200 kg, power consumption at the level approx. 20 A, weight approx. 32 kg, warranty: 5 years