As for airtightness, Class 4 Damper marks the highest efficiency, according to the european norm UNI EN 1751: 2003. Designed by APS Arosio Research and Development Centre, this damper relies on a Zama movement which guarantees reduced air leaks when closed. The set of gaskets combined with the structure, as well as special covering caps for the blades, let this damper reach the prestigious airtightness Class 4, enabling the most demanding builders to make up high efficiency AHU structures. A strong damper with an easy assembling, made up of top level materials for big performances.