Both the Model AST and ASTL were developed primarily for lifting, turning and stacking lightweight beams and structural shapes while a constant tension is applied to the lifting shackle. The horizontal shackle permits a beam to be lifted with the web in a near horizontal position by placing the clamp on the load with the shackle positioned over the web, and between the flanges.  With a beam lying in a horizontal position, and the clamp placed with the shackle overhanging the flange, the beam can be lifted, turned 90 degrees, and raised in a vertical position.