Class 1 & 2 receivers are light-duty and are designed for passenger cars and smaller Crossovers SUV's. A class 1 hitch can handle a trailer up to 2,000 pounds with 200 pounds of tongue weight. A class 2 hitch can handle 3,500 pounds with 350 punds of tongue weight.
A class 3 hitch is the most common found in full-size pickup trucks and SUVs. They have a 2-inch square receiver tube and can handle 8,000 pound trailers with 800 pounds of tongue weight with a ball mount or up to 12,000 pounds and 1,200 pounds of tongue weight with a weight distributing hitch.
Class 4 & 5 hitches are the heaviest duty hitches available. A class 4 hitch can carry 10,000 pounds and 1,000 pounds of tongue weight with a weight carrying hitch and up to 12,000 pounds and 1,200 pounds with a weight distributing hitch. A class 5 hitch can handle up to 14,000 pounds and 1,400 pounds of tongue weight. Both class 4 and class 5 hitches use the same 2-inch receiver tube as a class 3. Some class 5 hitches can use a 2 ½” receiver tube.