The wind tunnel enables calibrating velocity sensors in the range of very low velocities. Precisely and accordingly shaped measuring section makes it possible for generation of laminar reference. The measuring section is made of transparent SIMOLUX plastic, which allows to observe the positioning of the sensor during calibration. The velocity range that can be achieved in the measuring section is 0.05 to 5 m/s. On the special request the wind tunnel can be equiped with second section which allows achieving of velocity to 10m/s.