I use the one from EdgeMaker Pro https://secure.edgemaker.com/section...spx?prod_id=26
My fingers attest to the fact that it works...all too well.
Edit: I use the Yellow one with the finest grit. I figure my hooks never get so bad that I need a medium or coarse grit to get it back in tune. Five or six strokes on the fine grit gets it as sharp as it's ever gonna be.