CURT Xtra Duty Class 5 Trailer Hitch, 2" Receiver, Select Silverado, Sierra 2500, 3500 HD, Long-Bed, Towing Draw BarCURT Xtra Duty and Xtra Duty+ hitches begin a Class of their own, beyond Class 4 and beyond anything the standards dictate. Xtra Duty trailer hitches have a gross trailer weight capacity of 16,000 lbs., and the Xtra Duty+ goes even higher at an unbelievable 17,000 lbs. The tongue weight capacities of both the XD and XD+ are also increased to better accommodate the massive amounts of weight they can tow, rated at 2,400 lbs. and 2,550 lbs. respectively.