I have occasional bouts of tendonitis in my wrist, and I was looking for a comfortable mouse to use as I use computers regularly both at home and at work. Using this mouse has eased the pain I was experiencing and I would recommend it to anyone also suffering any form of RSI or tendonitis. As the wrist is at 90 degrees to the work surface, there feels less pressure than at 180 degrees, as you do with a normal mouse. I find myself moving the entire arm instead of just the wrist, too. An excellent product and this price was particularly great!