Bought this for my punk musician boyfriend, after his initial comment of "this looks like highway robbery" and some persisting he try it out, he actually finds the resistance great exercise. I could see how this is also a great tool for someone recovering hand mobility. Would recommend to all musician's girlfriend's who have run out of musically-relevant gift ideas.
I haven't used it much, but on the day my dad opened the gift we all used it and I loved how it could fit on all of our different hand sizes. Just tighten the straps, put your fingers in the little holes and you go exercise your hand. It's awesome and fun!