Rolling ThumberA Nemesis Grips original! This is an extremely humbling tool for training your thumbs. Place your thumb on the roller side, and fingers on the plate side. Because the fingers have nothing to latch onto, the thumb becomes the primary need for holding the lift. The interchangeable roller spins with minimal friction and will have the tendency to spin out of your hand the moment your thumb starts to weaken even the slightest! Make sure to squeeze real