I just got one from eBay. Literally only had it a few hours now but having used it I can say it definitely works out your whole lower arm. Obviously I'm yet to see if there are any long term benefits and wether it succesfully sorts the wrist problem I've been suffering from for a couple of months now, but it's looking good at the moment. EDIT: 10400 rpm so far, still haven't got my technique dialed though