2pc Primary Activated Carbon Cotton Filter Set for OMT120 Fume ExtractorFeatures Dual Layer Primary Filters: This primary filter set from OMTech includes 2 dual layer primary cotton filters for quick and timely replacement for your air purifier or fume extractor in long run. OMT120 Replacements: These primary filters are the exact replacement prefilters for OMTech's industrial strength OMT120 fume extractors. For optimal filtration, choose only original OMTech filters for your machine! Effective Filtration: Each of our