EXTREMELY EFFECTIVE: GripPro trainer is an extremely effective finger-hand-forearm strength and endurance trainer. , 3 LEVELS OF DIFFICULTY: GREEN-30lb. Easy , Black-40lb. Medium, and Red-50lb.Difficult , EASY TO USE & PORTABLE: GripPro trainer is very portable and easy to use, almost anywhere/anytime - at your desk, stuck in traffic, walking, on the treadmill, etc. , WHY IT’S THE BEST: 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. , WHO NEEDS IT? Few people appreciate how important grip strength is. It affects your abilities in many hobbies and pastimes and your performance in most sports such as: golf, tennis, rock climbing, basketball, baseball, water skiing, jet skis, mountain bikes, extreme sports, softball, Harleys, snowmobiles, and MORE!