This little Corky gizmo was designed for cyclists with drop bars. It's so named because you install it by "corking up" the end of the bar, and now you've got a handy rearview mirror (polycarbonate, not glass) you can flip out. It's attached via a ball joint, so you can dial in the angle.
Made by French bike accessories company The Beam, these run $38.
They also sell a Corky Urban variant for ordinary handles. (Same price.)
