But it's a cool product and when I test it by simulating a ...
This products works as advertised, but when they show you how to evaluate whether it will work for someone, don't buy it hoping that someone with a severe tremor will be able to use it.  If they can't keep a pen within the largest circle on their website, it probably won't work for them.  But it's a cool product and when I test it by simulating a moderate tremor, it's easy to see how well it can work.
Rating: 5 stars