i'm looking for the info that i saw on the 3 or 4 variuos types of short ram filter materials, some had a miles replacment and some had cleaners. there was one that did not have to be replaced at all, mabye only cleaned.there is a pic of one of these filters in the article, i think it was green. i have looked around for the last two days here but cannot find it. this info would be real helpful to my next purchase. THANKS! P.S. i won't be able to check this response until i get off work tonight 12:00AM, someone has too stack the beer at work, not kidding check profile.