Grip Pro Trainer is an extremely effective finger-hand-forearm strength and endurance trainer. It comes in 3 different levels of difficulty: GREEN - 30 lbs. Resistance BLACK - 40 lbs. Resistance RED - 50 lbs. Resistance How to use: Grip Pro Trainer is very portable and easy to use, almost anywhere/anytime - at your desk, stuck in traffic, walking, on the treadmill, etc. Try 3 sets of 10-60 reps a couple times a week for best results over time. Its also great for stress relief. Increase reps as necessary. Why it works: When compared to other portable hand/forearm exercisers Grip Pro Trainer has a great feeling in the hand and is superior to: Grip type balls-extremely boring and mostly therapeutic; metal spring devices with handles-awkward, uncomfortable and due to the fulcrum of the spring give an uneven exercise; hand held gyros-difficult to use.