Unaffected by humidity and resistant to a wide range of chemicals, the new Multi-Guard surface pocket filter is made with a dual layer of electrostatically enhanced synthetic fiber media that promotes high efficiency with low resistance and outstanding dust-holding capacity, says the manufacturer. The company says the electrostatic charge applied to the media increases the filter’s initial efficiency, especially on particles less than 1 micron. The filters are available in three efficiencies: 70% to 75%, 80% to 85%, and 90% to 95%.