EASY TO USE: Filter odour and smoke upon exhale. 3-stage activated carbon + HEPA filter allows you to reduce secondhand smoke for roommates, family and neighbours. HIGH QUALITY ALUMINUM: Aircraft grade aluminum alloy casing – no more cheap plastic filters, this is designed to be long-lasting and elegant. REPLACEABLE CARTRIDGES: Instead of buying a whole new filter, simply replace with a cheap, easy to change replacement filter! Also has removable mouthpiece and cover for easy cleaning.LONG LASTING: Lasts up to 500 exhales before needing to be replaced.