The innovative new Heavy Grips are designed for athletes who want to take their grip strength to higher levels. These sturdy aluminum-handled hand grippers are made with industrial strength springs and require more force to close and will develop greater strength when used. The 100 lb. hand gripper requires 100 lbs. of force to close while most hand grippers require only 40 - 60 lbs of force to close. The Heavy Grips are available in 50 lb. increments ranging from 100 lbs. all the way to 350 lbs. The Heavy grips are an excellent tool for anyone looking to dramatically increase their hand and forearm strength. This is excellent for wrestling or other grappling-intensive sports such as jujitsu.