Don't remember where I saw it advertised, but it was an overpriced metal rod with a slit in one end. You put strips of sandpaper in the slit and clamped the other end in a drill(press) for sanding uneven pieces. Today I sawed off the handle of a foam paint brush and made a 1" cut into the end with the band saw. Folded a 3 layer thick piece of 80 grit sandpaper. 1' X 2 1/4" final size. Used it to sand a basswood woodcarving. Really liked it. Check the last end of the fold, as it relates to the rotation direction of the drill. If it is wrong, turn the sandpaper upside down.
jerry