The Handmaster Plus Finger Trainer Set – simple applications. The Handmaster Plus Finger Trainer Set consists of 3 training devices with resistance levels of light, medium, and firm. The application is very simple: guide your thumb and 4 fingers through the designated loops. Spread your hand within its natural range of motion. Then, press the ball in the center together. Ensure a smooth movement flow. The rubber loops can be pulled out of the ball. The compact hand trainers are ideal for fitness and home workouts, as well as for therapy and rehabilitation. Product details: Balls made of coated foam, ball diameter: 7 cm, includes replacement rubber. Product type: Wrist trainer.