Just the facts! Picture shown with two stage (M-class) pre-filter attached This filter should last 3-5 years for non-smokers. -The main filter is reuseable and can be recharged after 4 years. -The pre-filter is a bonded two stage (M-class) replaceable. -The pre-filter is the key to longevity. -Changing the pre-filter offers fresher air, not filtering through aging organic garbage like all other filters. -Pre-filter removes mold, pet dander, pollen, skin cells, etc. The main filter is a three stage, capturing down to the molecule, able to trap .0007 diameter. The Adsorption filter contains up to 50 times more carbon than typical carbon pre-filters, therefore is more effective and lasts up to 50 times longer.