The heavy grip hand grippers are built for athletes who want to take the training of their grip strength to the next level. It is also ideal for martial artists, climbers, golfers and anyone else who wants to improve their hand and forearm strength. These high-quality knurled aluminum-handled hand grippers are made in 50lb increments from 100lbs to 300lb so that you can train your grip similar to training any other body part-- by increasing resistance. Advanced level is suitable for those who have done some advanced grip training. This heavy grip takes 200lbs (91KG) of pressure to close