‘Flow’ is a ventilation device, specifically designed for stucco facades. Because of its discreet integration into the façade 'Flow' provides an innovative alternative to the known ventilation grates. The smooth design and seamless transition with the wall, ensure that the aesthetics of the facade design are no longer disturbed. 'Flow' and the wall become one. It is set during the plastering of a house, and is primarily intended for private homes, but can also be placed in other projects. The assignment for this book was to design a new look and feel for ventilation grilles. After brainstorming, I started developing different concepts. From these, I selected the best concept: a grid incorporated in the outer stucco. Subsequently I gathered information about the plastering process, and using this information, I made and plastered a prototype. Starting from this prototype, I made two other variations of the initial concept. Eventually I chose a form that is a compromise between design and the possibility of plastering the product. I further developed this final concept and finished with a 1:1 scale model.