All the Utopia laminar ceiling have a octagonal shape 3,2 m by 3,2 m; there are 8 filters with efficiency H14 and their shape is trapezoidal. The absolute filters have a double density; greater in the centre of the ceiling so to have a higher speed and therefore guaranty a better effect of expulsion of the contamination from the aseptic nucleus. With the same filtering ceiling area the trapezoidal filters have a covered area greater by approximately 20% than the traditional standard rectangular filters. Utopia's ultra-clean ventilating (U.C.V) system, which is unique in generating an ultra-clean zone free from peripheral entrainment of contaminated air and creates a clear zone larger than its diffuser area, giving protection over instrument tables in addition to the immediate surgical area. BSL4.