This wrist strengthener is made of heavy duty carbon steel spring, which is stainless and durable. The soft and thickened minimize hand and forearm fatigue. It is designed to improve strength, power and speed in the wrists, fingers and forearms. Strengthens and builds flexor and extensor muscles. No assembly required. Adjustable stabilizer pad for regular or reverse wrist curls. The adjustable Anti-resistance nylon ribbon for both small and large hands, men and women.