Logitech MX Vertical Advanced Ergonomic Mouse

Excellent product. Requires far less hand movement to navigate a screen. The mouse buttons do take a little practice getting used to, I tend to find I click too far back on the button and need to position my finger further forward on the mouse for the 'click' to register, but that is largely down to my seating position, which is slightly further back than is ideal (due to contention between knees and desk).