The Dynaflex Docking Station with Blue Powerball Strengthening System is a hand and arm strengthener designed for home use. Made of durable plastic, this sports training aid features a striking blue color and is part of the Sports PRO model. This unique docking station allows users to easily enhance their gym and training routines by incorporating the Dynaflex Blue Powerball, providing a convenient and effective way to improve strength and fitness levels.It increases your range of motion and conditions your arm and shoulder muscles.It reaches up to 13 rpm and creates 35 pounds of torque resistance, Docking station activates gyro within seconds, requires 2 AA batteries. Perfect for those looking to add a new dimension to their fitness regimen, this product combines practicality with innovative technology for optimal results. Please feel free to email me with any questions. I want you to be happy with your selection.