Comfortable Grip: Covered with environmentally friendly TPE materials. Soft and prevents it from accidentally slipping out of your hand when you get sweaty. Ergonomic design suitable for seniors and teenagers. High-quality materials: The use of particularly high-quality materials and extra-strong steel springs makes it durable. Adjustable resistance: Adjustable resistance from 10 kg to 50 kg. Hand trainers are ideal for training your finger, hand, and forearm muscles and improving your grip strength! HAND MUSCLE TRAINERS: Climbers, bodybuilders, muscle builders, tennis players, drummers, guitarists, pianists, and massage therapists. Improve the strength of your hands, fingers, wrists, and forearms. Improve the grip strength of your hands and fingers, endurance, flexibility, muscle tone, and fine and gross motor skills.