Stropping a razor with marbles?

Several months ago on the Bay I say an auction for an item claiming to be a razor sharpener. It looked like a cheap contraption made out of a wire handle and some marbles. The auction was posted here by someone else and if I remember correctly it was decided that it must be some sort of scam. Well now I see this auction, only this one looks like a well made device. At this point I have to assume that these were actually used for something once upon a time. Does anyone here have any more info on what they are and if they are really meant for razors?

check this out Razor Sharpeners and Stroppers
(I think it is for safety razor blades)

annalyzing the concept of stropping, the action is supposed to straighten out the blade (yes/no?) and i could see how this might do it but it could also bend and break the minuscle edge...i think it would be an interesting device and if i had some disposable income i'd give it a test but i'm flat broke :-\