Adjustable Dumbbells

The Paraball Dumbbell (adjustable dumbbell) is one of the most versatile tools for functional and strength training. It's patent pending design allows you to add weight asymmetrically to both sides of the handle, providing an additional axis of resistance to every exercise you can think of with a dumbbell. 
Besides the unmatched variability of exercises, both isometric and rotation wise, this is also one of the best tools for grip strength.

It's unique weight system allows you to adjust the leverage and center of gravity of the weights providing different muscle stimulus for the exercises.