The peculiar feature of the Formula 190 model is the patented system of adjustment of the clearance between the rotating blades and the bottom of the box frame, obtained varying the position of the frame in height. In this way the volume available for the soil during work varies and so the level of refinement of clods. This adjustment is obtained thanks to 4 threaded bar connected to each other, or 4 hydraulic rams fitted with stop valves. Because of this feature this unit is particularly versatile and can be effectively used in many different working conditions. When soil is dry a better refinement can be obtained by positioning the frae in a lower position, while soild build-up can be easily avoided in wet conditions by increasing the working height of the frame and so the clearance underneath.