The deluxe version of the hand trainer is the perfect training device for your living room, office, or on the go. This finger dumbbell significantly strengthens your hand, arm, and forearm strength. The aluminum handles feel comfortable in your hand. The spring coils made of black iron are of very high quality and ensure a long lifespan. Exercises with the hand muscle trainer also help to reduce stress. Grip length: 9.5 cm. Diameter: 18 mm.