The tap series INDIGO and INDIGO_Rack stands out because of its ribbed handle. A surface engraved with linear grooves, a sequence of parallel traces and signs that embellish the cylindrical volume, giving a dynamic look to the overall image of the tap. The sculptural knob becomes a jewel in INDIGO_Rack, the collection of taps with clear geometries and rigorous lines. A composition generated by the perpendicular intersection of well-defined trajectories that distinguish the entire Indigo series, which finds exclusivity and a distinctive trait in the knob, with the characteristic of a diagonal cut that dissects the volume. Form and function are integrated in this version of the mixer, because the grooves that decorate the knob and identify its image at the same time contribute to increasing its ergonomics and facilitate the grip during the operation of opening and closing the water. As often happens in antoniolupi proposals, the technological matrix and the references to the components of an industrial object become an expressive detail of the collection.