Replacement filter bag for filter tower DN 200. This filter bag effectively removes coarse impurities from the sucked-in air, thus extending the life of the main supply air filter in the heat recovery unit. Synthetic fabric from a leading German manufacturer is used for production, which does not contain dangerous glass fibers. Thanks to filter class G4, which mainly separates coarse dust and thus only presents a negligible resistance to the airflow, no modifications to the existing ventilation system are required. One pack contains 3 replacement filter bags.