Incense paper differs slightly from joss paper, though serves the same purpose. Incense paper is a yellow coloured paper with a gold foil printed on it representing a gold tael or with a silver foil representing a silver tael. A tael is a weight measurement similar to the Thai bath, part of the Chinese system of weights and the currency. A further form is a single-coloured paper with one side having a rougher surface and the other side a smoother one. Such papers come in varying colours and are supposed to represent cloth for the ancestors.