Not sure, but they once had a small section of one of the straight razor blades about the size of our present safety razor blades that fit into a holder similar to our present safety razor handles.. You removed the blade and placed it into a holder similar to this to hone it. This looks like the part used to strop or hone it. hence the roller. It would go flip flop changing the edge being honed for every forward or back movement. hehehe. Possibly an older version of a Rolls?
Tropical Tramp