The filter is placed on the Vita device before the treatment tip is attached. The filter sits above a built-in mesh filter—both protecting the device's motor from collecting any debris pulled from the skin. Both Vita Trio and Solo come with 50 filters. Filters are to be replaced with each facial treatment—you'll notice how much dead skin you collect via microdermabrasion—pop that dirty filter out, replace with a new one and you're set for your next treatment! Additional replacement filters can be purchased here; subscribe and save to ensure you never run out of them!