The Sports filter Pack contains two replacement filters for use in the Respro® Sportsta™ Mask. The Sports filter has sub-micron filtration capability and is usable in both countryside and urban environments.This Sports hepa-type filter is able to trap particles less than one micron in size (sub-micron) and is more than capable of the removal of PM2.5 respirable particulate matter found in both urban environment.This filter can be used with any Respro® mask (with the exception of the Metro™ mask) provided that it is the same size filter as the mask size ie; large filter - large mask.