Wrist rollers are simple devices that provide effective forearm workouts. They are rods with weights attached by a short rope which you twist one way to raise the weight and the other to lower it. They're easy to make yourself - here's how to construct two different types of wrist roller: the conventional long skinny one, and a short fat one for a remove-the-lid style workout. Both can be had commercially for ~$20 or ~$45 (the "Forearm Blaster" and "Twist Yo Wrist") respe...