IMTUG: Two-Finger Utility Gripper is a small wonder that will take your grip strength and hand health to new heights. Grip strength involves your thumb, as well as your other four fingers: your thumb is key to your pinch grip and your other four fingers are key to your crushing grip. IronMind recognizes that your fingers differ in both length and strength and devised a tool that would help train one or two fingers at a time, as well as your thumb. Use as a standalone training tool or in conjunction with a Captains of Crush Gripper. IMTUG4: This is the mid-level, strengthwise, of the IMTUG series--the perfect starting point if you are working on a Captains of Crush Trainer, No. 1 or No. 1.5.