... ;efficiency: 60~98% by colorimetry (ASHRAE 52.1-92);efficiency rate: F6, F7, F8, F9 (EN 779). We are professional supplier ... medium filter is mainly used as primary and/or medium filtration elements.It is widely used in pharmaceutical, food processing, precise ... %, 90%, 95%, 98% by colorimetry (ASHRAE 52.1-1992)Efficiency rate: F6, F7, F8, F9 (EN 779). We have exported such ...