Keep dust, dirt, and debris away and breath in clean air with this mask. F1 is our standard filter consisting of two filter layers, the outer particulate filter, and the internal active carbon element. The outer layer of the F1 filter is capable of trapping particulates down to .1 microns in size. The inner layer, known as the Active Carbon element is effective towards fumes and odors. Combining the two technologies, this filter has been laboratory tested to be 99.9% effective.