Pronation / Supination O-HandlePronation and supination are critical in developing strong wrists. This O handle allows you to do both! Where the D handle may work for some pronation supination, the full circular design here provides a more complete range of motion and smoothness throughout. Very popular with armwrestlers but also very useful for other sports and disciplines requiring robust wrist stability. Comes in various handle diameters to suit different hand sizes or provide