The heavy-duty aluminum driveshaft has all the advantages of our lightweight aluminum driveshaft with the exception of heavy duty 1350 series billet aluminum weld yokes and heavy-duty 1350 series(1 3/16" x 3 5/8") u-joints. They feature a 3 1/2" x .125 wall aluminum tube. Each driveshaft is balanced and includes 1350 series u-joints. These driveshafts offer an 8-lb. weight savings over standard steel shafts and are rebuildable. WARNING: These driveshafts are not for street use or drag racing.