USA AH-4 hitch end cap; ball with plug (fits 51mm x 51mm socket)
Ball hitch / adapter for American cars. It has European homologation. Fits mounting sockets with a square cross-section of 51mm x 51mm. The set includes a protective plug with a pin. The ball itself, in case of wear, can be purchased separately (ball with M22 thread). Its diameter complies with European standards (50mm). The distance from the mounting hole to the center of the ball is 250 mm; the ball head itself is located 20mm above the center of the mounting hole.