Power Twister Original Safety Dynabender Heavy Tension 10130A Ader Power Twister Original Dynabender Heavy Tension perfect for building your hand, wrist, forearm, bicep, tricep, and back muscles. Heavy duty high grade music wire (5.5mm), Black/Purple grip and spring with patented safety wire, Easy to carry and workout anywhere. Best original design & patented by Ader Sporting Goods Item #10130A. No shipping outside of 48 states, APO or FPO