Features:The most versatile mask available, giving excellent filtration against most types of pollution a cyclist is likely to encounter.,Uses a Dynamic Activated Charcoal Cloth filter to filter the worst of urban pollution.,Also uses a HepA-type filter to screen out sub-micron pollutants such as pollens and respirable dusts.,Includes two Techno valves to allow easier exhalation, which is particularly important as they release heat, water vapour and Carbon Dioxide.,Comes in two sizes, with a contoured shape for a good seal and comfortable fit and Velcro pads for easy application.,Made from hypo-allergenic Neoprene giving a comfortable and secure fit.,The filter is replaceable, and is designed to be effective for at least 1 month in normal daily use.,.