Evoluent VerticalMouse VMDM Right-Handed Ergonomic Wired Mouse - Original Brand Since 2002 - Perfect for Office Work, Computer Use & Reducing Wrist Pain

This is the most comfortable vertical mouse I have tried. It holds your hand the most sideways, which is very important for eliminating lateral wrist motion. I tried a cheaper vertical mouse and returned it before coming back to Evoluent, man it was not even close. You don't have to twist your arm, pinch your fingers, make any weird motions, your hand just sits there. Compared to other mice this one is like AHH so natural. I LOVE having 3 finger buttons, being able to use middle click for opening links or pasting (usually the mouse wheel click on a normal mouse). Mouse wheel can also scroll horizontally while holding down one of the thumb buttons. I never knew I needed these two features in a mouse but I now use them constantly. The Evoluent software (Windows only?) allows you to remap the buttons for many additional functions.One change from the older model Vertical Mouse 4 I do not necessarily like is they have made the 3rd mouse button smaller. This is the button you press with your ring finger, whereas on the previous model it was pressed with your ring and pinky finger, definitely easier. I cannot comment on the battery life, this is my first wireless version and it has not run out yet. It takes 1 AA battery.Pros:Most comfortable vertical mouse available (this is #1)Lots of additional functions for common activities.Contoured finger buttons feel nice.Includes battery (!!) and extension cord for the wireless receiver (I have not needed to use it so far)Looks cool (better than in the picture), feels more premium compared to old model, more on par with mice at this price point.Cons:ExpensiveMouse button 3 harder to press than the Vertical Mouse 4 now that you can't use two fingers.