The CanDo Magneciser horizontal table-top shoulder exerciser offers ultra-quiet magnetic, bi-directional resistance to exercise muscles and joint of the shoulder, arm, wrist and upper body.. Arm adjusts from 13 to 22 inches to adjust the arc of the horizontal shoulder wheel. Each unit comes with a fully automatic 5-function digital LCD display; speed, elapsed time, calories, distance and scan of all functions. Resistance is controlled by turning the resistance knob. Units use 2 AA batteries (included).