My NSD powerball cured my RSI and carpal tunnel syndrome in double quick time. I play guitar a lot and was sick of playing through pain. I do not sell this product, nor am I affiliated to it, this review is written in the spirit of fair play to a product which actually delivered what it promised.
Within a couple of hours use I could tell the powerball was working, I had tried acupuncture, osteopaths and spent hundreds on treatments, I even tried resting for 6 months (if you play guitar you will know this is extreme punishment) but it just didn't help. I would say it took around 2-3 weeks use to regain my full range of motion in my left wrist and now after a couple of months use I can play all day again.
As ever do make sure you avoid knock off products, the genuine item is branded NSD and is available from a few reputable uk ebay sellers