DUETTO® calender layouts are based on the possibility to maintain at process disposal two or three additional spare rolls having different pattern designs and/or surface finishing. Thanks to this unique arrangement it is possible to easily switch from one engraved roll to another one reducing the traditional set up times, since it is no more necessary to cool down, replace and warm up again the calender rolls. Just moving the DUETTO® revolver, the new roll is quickly ready to be used already warmed up. Possibility to let the calender threaded without rolls action (by pass) due to the revolver configuration.