Arum manis in this case is a variant of cotton candy (which is confusingly also called arum manis here) that sandwich a lump of hairy fibrous sugar thread inside thin crackers. Customers never confuse the two regardless of name because of the characteristic of the paddler.
A small beam made of bamboo is used to carry a couple of wooden cabinet, which then act as a base for a pair of aluminum cans. One can is filled with stock of pre-made fibrous sugar thread, usually artificially colored red. While the other can is either used as additional stock of sugar thread or a nice dry place to stock the crackers. Another strange characteristic, arum manis peddler is almost always an old person. My guess is the weight of arum manis has something to do with it.
With this particular peddler, a piece of arum manis sandwich cost me only 2000 rupiah, or about a quarter of US$. Other arum manis peddlers sell by a plastic of five pieces.