The Zero Tension Mouse is a vertical mouse that allows you to move in any direction without bending the wrist or moving the fingers, while keeping the arm and hand in the more ergonomic vertical position. This is a great idea for those who have chronic problems with RSI or have experienced pain in the wrist and fingers.

ExtremeTech's review takes a good look at this vertical mouse. Although they acknowledge that it's "funny looking," it amounts to a whole lot of worth for those who need it, or those who want to take preventative measures against RSI and other ailments.

Shake Hands with the Zero Tension Mouse