A coupling is a hardware that is used to connect two shafts. During motion, these couplings do not allow the shafts to part off, but it is dependent on the amount of torque applied. Uttermost care is taken to manufacture this hardware accessory. Though this is not a fun play system, it plays an important role in proper and smooth functioning of the various systems. The Coupling is used with our standard tube saddles to a 1.9-inch outside diameter pipe.