The Techno Filter Twin Pack contains two replacement filters for use in your Respro Techno Mask. The filter is suitable for use in heavily polluted environments, i.e. air that is full of diesel particulates and respirable dusts that lodge deep within the lungs and air sacs. It is a combination of the Sportsta filter and the City filter giving you both sub-micron particle filtration with gas and vapor filtration. What this means is that the filter is able to trap particles less than one micron in size. With the capability of filtering VOC, the Techno filter is the best available in our range for dealing with the broad spectrum of pollutants that are out there in heavily polluted urban environments.