SupraBar Butterfly Tri-bar Triceps Press Down Bar. Attached to any cable machine like any other tricep bar. Take your triceps training to a whole new level with 3-D realtime pronation/supination while performing triceps press downs! By catering to the natural tendency of twisting your wrists freely during the exercise movement, joint stress will be greatly reduced, and at the same time will allow the triceps to flex to their maximal capability at the end of each rep. This can only result in one thing: Incredible Gains!