Strength: Light. The Handmaster Plus finger trainer for effective hand muscle training is easy to use and highly effective. Unlike many other training devices, it trains not only the flexor muscles for gripping but also the opposing muscles for opening the hands. Simply guide your thumb and four fingers through the designated loops. Spread your hand within the natural range of motion. Then, press the ball in the center together. Focus on a smooth movement flow. The rubber loops can be removed from the ball for separate exercises. Product details: Balls made of coated foam, ball diameter: approx. 7 cm, includes replacement rubber. Available in 3 resistance levels: Blue = light, Red = medium, Orange = firm. Contains latex. Product type: Wrist trainer.