I have got a ton of these (at least a half dozen or more):

http://www.midwayusa.com/product/886556/gerber-pocket-sharpener-ceramic



Never actually used one. I have no idea if they work well or not. I add them to my orders from Midway because they are one of the cheapests item they have with free shipping. So when I add one to my regular order that normally would have, say, $15 shipping charge, the addition of this item lowers the overall shipping charge to something like $5. So I save $10 by adding a $2.99 item, for a net savings of $7. Can't beat that. I'll bet Midway is wondering why I order so many knife sharpeners! They're all sitting in my man-cave, still in their packaging. I could probably return them for a refund to increase my savings, but that would be unethical in my mind, so I just keep them. I guess I could use them for stocking stuffers at Christmas (but I think everyone in my family already has a handful of 'em!)