This thing. Travel version of the Arc Mouse. Replaces middle button/wheel with solid-state slide control that includes scroll, page up/down, and middle-click.

Except I lied there. It doesn’t actually support middle click. In his infinite wisdom, designer Young Kim made a click at the top of the strip, where your finger naturally falls, send a page-up keystroke. Clicking at the bottom of the strip sends a page-down.

Clicking the middle of the strip does nothing at all. You double-click the middle of the strip to generate a single middle-click. Middle-click-and-hold activates the annoying drag-scroll mode that I’ve never seen anyone use deliberately. Usually they end up trying to figure out why their mouse stopped working normally.

And why do I know the designer’s name? Because the only two things on the product support web site are an interview with him and a “lifestyle video”.

And why did I buy one? Because the last several MS mice I’ve bought had poorly-engineered scrollwheels that simply stopped working after a while, and I thought the solid-state version might be a step up. It looked nice at the company store, and didn’t suffer from the same heavy-spring problem that the right mouse button on the standard Arc has.

So, if you’re one of those two-buttons-is-enough Windows people, and you don’t mind risking the loss of the little USB dongle (held in place on the completely-flat underside of the mouse by a strong magnet), it looks like an excellent lifestyle accessory, and a decent mouse.