In the gym for specific forearm work i do a mix of barbell wrist curls supersetted with one-armed reverse wrist curls holding a plate. Also do behind the back wrist curls with a barbell and reverse curls using a false grip with a further curl of the wrist at the top.
I made myself a wrist roller a few years back just from a 1" diameter room handle. It's about 2 feet long long and in addition to the eyelet in the middle for the rolling action, i also screwed an eyelet into one end. Allows me to attach a weight an/or chain and opens up a whole other set of movements. Hammer style extensions, pronation or supination movements. Let's you work in more planes which can only be a good thing IMHO.
