【High-quality carbon steel spring】This hand trainer is equipped with a carbon steel spring, which can generate up to 45 kg (99 lb) of pulling force. The spring surface is smooth and well-lubricated, providing a frictionless rebound effect, ensuring smooth exercise and avoiding the risk of pinching fingers. 【Ergonomic Finger Dynamometer】The independent anatomical five-button spacing design specifically improves finger strength, grip durability, and palm coordination. A must-have for climbers and musicians. 【Comfortable Hand Trainer】The ABS shell adopts a three-layer soft coating + TPE to cover the buttons, which is durable, soft, and comfortable, which can reduce joint pressure and will not cause hand injuries even if you train for a long time. 【Portable Hand Strengthener Ball】With its lightweight design, it can be used anytime in the office, during travel, or during physical exercise. It relieves stress while quickly building hand strength. 【Multifunctional Finger Strength Ball】The