NSD Power Winner's Precision Sterling Spinner Gyroscopic Wrist and Forearm Exerciser with Digital Speedometer, and Heavyweight Zinc Rotor and Stainless Steel Shell Solid ZINC rotor provides a whopping 41.3 lb-in of resistance at 10,000 RPM Stainless steel shell construction, anodized in silver color and polished to a mirror like shine for professional and amateur athletes alike. Computer balanced inner gyroscopic rotor for VIBRATION FREE operation Ideal for building muscle and grip strength for athletes. Combine with PB-588HC Spinner for BEST result! Performance Digital LCD counter SM-02 displays total revolutions in multiples of 100s, current speed in RPM, historical top speed in RPM, and a physical strength index