A ripple ribbon tube is a piping-bag nozzle that extrudes icing, cream, or dough in a ribbed ribbon shape. The nozzle’s flattened, serrated opening forces the mixture into a band with fine ridges along its length, giving piped borders, cake trimmings, and biscuit shapes a decorative fluted texture in a single motion. It belongs to the family of specialist tubes, alongside star, plain, and petal nozzles, that let decorators produce professional finishes without hand-carving. The mixture must be the right consistency: too stiff and it tears, too soft and the ribs collapse. Pastry chefs use ripple ribbon tubes for edging gateaux, piping buttercream bands, and forming the ridged biscuits sold in bakeries.