ITA forks are forklift forks that have clips welded on the back of each fork allowing it to slide onto top and bottom rails of your frame or machine. They come in different classes depending on how much weight they can handle to move and pick up. ITA forks typically range anywhere between class 1 up to class 5. The clips on the back of each fork are a certain distance apart from the top and bottom clips and that’s what determines it’s class. Typically most local farmers have a class 3 or lower and most commercial machines are class 3 through class 5. Like stated in the previous comments the class is determined in the spacing between the two clips on the back of the forks. Class 1 is 13 inch spacing. Class 2 is a 16 inch spacing. Class 3 is a 20 inch spacing. Class 4 is a 25 inch spacing. Class 5 is a 28-3/4 inch spacing. Class 1 lifting capacity is 2,200 pounds. Class 2 lifting capacity is 2,200-5,500 pounds. Class 3 lifting capacity is 5,500-10,998 pounds. Class 4 lifting capacity is 11,000-17,600 pounds. Class 5 lifting capacity is 17,600-24,200 pounds.