Rolling BarrelWork your vertical strength in nemesis fashion! Place your fingers on the roller to get them squeezing hard, or place your thumb on the roller for a more difficult challenge. You can even hold it with the pinky side down (i. e. index is at the top of the barrel) to work the wrist. The roller sits between bearings to allow smooth action and minimal friction. The roller is interchangeable with other 5" Nemesis rollers and can accommodate up to 1. 75"