Our app “C.A.T.S. duct calculator” is getting more popular day by day – also internationally! Up to now there have been more than 20.000 downloads. Our duct calculator lays out like a conventional channel slide round, square and oval ventilation channels. In addition, it calculates the channel surface and the insulation allowance. Both the metric system (mm) and the imperial system (inches) are supported. The android version of this app is available in Google Play Store in English, Italian and German and it is for free.