A friend sent me this pic and wants to know. I've never seen one.
Honestly, this reminds me of nothing so much as my mother's old knife sharpener. It had a few tightly spaced ridges, like on this gadget, and you ran a knife between the ridges to quickly sharpen it.
Readers, can you identify this gadget? Ever seen anything like it?
(Image: via Andrew Scrivani)