Air flow range: 500-27000CFM Backward propeller is made of ST37 steel. The material of the nozzle housing is copper sheet It has an explosion-proof electric motor of the brand requested by the customer Made according to standards: EN80079–37:2016 and EN80079–36:2016 and EN1127-1 and EN14986:2017 After balancing the fan, the amount of vibration is validated according to the ISO14695 standard.