Ventilator HEPA Filter Media, Pleated PP Filter Core, High Efficiency Bacterial Virus Filtration This polypropylene pleated HEPA filter media is the core filter element of the ventilator HMEF/BVF filter. It is engineered to capture fine particles, bacteria and viruses in airflow. It achieves BFE ≥99.999% and VFE ≥99.999%, and can trap particles as tiny as 0.027μm, offering reliable airway protection for patients during respiratory treatment. The filter relies on four major