Blackcell Silica Gel Hand Grip Forearm Strength Gripper 30, 40 & 50 Lbs Full SET of All 3 Weights It is an extremely effective finger-hand-forearm strength and endurance trainer. It comes in 3 different levels of difficulty. It is very portable and easy to use, almost anywhere/anytime - at your desk, stuck in traffic, walking, on the treadmill, etc.