HEPA filter – Mini pleat design HEPA (high efficiency particulate air) filters which are tested and certified to a minimum efficiency of 99.997% down to 0.3 microns and 95% as small as 0.1 micron. They incorporate a series of webbing between the pleated media. This feature not only guarantees even spacing for full filter coverage between each pleat, but also alleviates the possibility of airflow vibration or collapse.