More info on mask...

"The most versatile mask available, providing 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, and releasing heat, water vapour and Carbon Dioxide from exhaled breath. 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 regular daily use."