To develop that big flexor/pronator belly, you need to use wrist flexion. Really heavy wrist curls bother a lot of my lifters' wrists, so we usually go for sets of 8-plus and seek a pump rather than maximal strength.
Wrist rollers are better suited for heavy wrist flexion, and this version is especially challenging since the resistance increases as you roll.
The Atomic Dog's out in the nuclear doghouse. (He chewed up Tim Patterson's favorite workout shirt.) As such, TC wrote a plain ol' regular training article instead of his usual hallucinogenic-mushroom fueled rant.