The application is used for calculating air velocities in fabric ducting and diffusers. Upon entering a given airflow, the velocity for the given size is displayed. Upon changing the size, we get the velocity for the given airflow. Values can be entered by moving the ruler or by typing particular values. The color of the speed scale signalizes suitability of the calculated velocity. Red means an unacceptable, orange risky and green suitable velocity. Blue signalizes excessively dimensioned. Yo