content: This is my second Trackball mouse.We have been using them for over 4 years now. I love them as do my children. There is almost no wrist movement necessary which reduces your risk of Carpel Tunnel. These are great for everyone. They do take a few days to get use to, not having to move your arm all over the place. When I now try to use a "normal" mouse, my entire body tries to move with it, it feels so odd to have to move your arm around to get it to function. I recommend this mouse for everyone, especially people that do a lot of work using a computer or gaming.Also, I received it the day after I ordered it! Absolutely fantastic service!