The CanDo Twist-Bend-Shake bar is a versatile exercise product available in 2 sizes: 24 and 36 inch long, and 6 resistance levels per size. It can be used to perform three distinct forms of exercise. TWIST: Place both hands on the bar and twist the bar by flexing one wrist and extending the other. BEND: Place both hands on or near the ends of the bar, and keep your hands in position while exerting force to bend the bar that will flex the bar in the middle. SHAKE: Place one or two hands at one end of the bar and shake (push, pull, or rotate) the bar which will cause the bar to flex. The resistance needed to control the bar increases as the amount of flexion increases. You can control the amount of force needed to "work" the bar by slowing down or speeding up the flexion of the bar, or changing to a different resistance bar. For all exercises, resistance can be changed by changing the distance between the hands and/or by changing to a different resistance bar. The 24 and 36 inch long rubber bars utilizes the same graduated progressive color code as other CanDo products (tan - xx-light, yellow - x-light, red - light, green - medium, blue - firm, and black - x-firm). Consistent bar diameter and length throughout resistances means you use the same muscles with each resistance.