Spinning Grips... The ultimate grip strength training tool:
Hulk Handles are a very simple versatile fitness training tool designed to help a wide range of athletes and fitness fanatics level up.
 
Better Dead-Hangs and pullups;  The handle wants to spin, so you're not relying on friction at all.  Generally we'd say it's 3 times harder than hanging from a fixed bar. (If you can one are dead-hand for 30 seconds on a Hulk Handle, you are a Beast!)
 
Better Muscle-ups and Dips;  No sketchy false-grip necessary.  The handles rotate, so you can keep that thumb wrap tight around the grip as you make the transition.  (Hulk Handles are a lot more comfy than gymnastics rings as well)
 
Tougher Ninja Grips; Replace that line of travel rings with Hulk Handles and your qualifier course is now a finals course :)
 
Cable Grips & Resistance Bands: Attach to any cable machine or resistance band to improve your workout.  No more raw hands burning on rubber.   Hulk Handles let you focus on gains, to grip grief!