SideWinder® Revolution 2.0 Premium Black 

#1 Premium Grip Strength Device In The World Laser Engraved SportGrips Logo Made In The USA 100% High-quality anodized aluminum Transform your grip and forearms: Variable resistance provided by the knob at the top of the device means suitable resistances for everyone **This product should last you a lifetime with proper use. That means turning back the knob at the top of the device to the default setting after each use. This ensures the springs stay resilient and do not wear.