That trailer was made by a small Iowa company called Mini-Toys that was bought out by Ertl. Mini-Toys made a line of implements that no one else was doing, using plastic injection with rubber tires. When Ertl bought them some bases became metal and the tires went plastic. This trailer came in several basic implement colors and many are still available at toy shows and on ebay.Great models. Who makes that Awsome trailer in the first pic ??