Austin Air Healthmate Plus 450 with almost new filters 5000 RMB The new filter is rated to last 5 years, and only has a two months on it. Just the filter itself is worth more than what I am asking for the unit. The 450 is the top of the line for large rooms as a full size air purifier,with the best filter that is rated to lasts five years (but I changed mine after two years, given the conditions in Beijing). It is much cheaper to operate than the IQAir, which requires much more frequent filter replacement. The filter itself is worth more than what I am asking, so its like getting the machine for free. I also have a large collection of 3M masks from America. Many different kinds, more than I'd every need for myself and my family. New in the box of course..