Available in different sizes, the SPM is an effective and robust iris damper for the measurement and adjustment of airflow. It provides enhanced choking ability. The SPM has a range of specifications, including low sound level as well as centrically formed airflow and fixed test points for precise measurements, The device can be used for supply as well for air extraction.

The damper is made from galvanised sheet steel and is fitted with a rubber gasket tested for casing air-tightness in class C according to EN 1751. It has an adjustable aperture which, in combination with a centrally situated sealing rubber ball, can close the entire cross-section. The SPM iris damper is available in sizes ø 160-400, 300 and 315. The damper should be installed in accordance with the distances required to minimise airflow deviation.