I've been buying these for a few years now and they just changed how the black filter is made. I'm not a fan of the new material at face value. It looks like a way cheaper quality material and one that I've never seen before in any HEPA filter. I'm now happy about the change so far. I'm still undecided if the change has degraded the quality of the filter in general. It also makes me question whether the white filter design was also cheapened. I was pretty happy with the Gem Guardian until now.

UPDATE:

I've had this new filter in for about a week now and I was shocked how much dust was already on the black filter already. I'm thinking this new style filter actually filters out more than the old one does so I'm increasing my rating to 4 stars now. I also washed the black part and it didn't fall apart as expected and was surprisingly easier to clean than the older one. The old design would have dust getting stuck inside the holes of the filter and I'd have to wash it for a while before i could get everythign out of it. The new one seemed to clean up much easier because the holes in the filter aren't as big. It cleaned up well and didn't degrade like I expected. Overall I'm actually liking the new design better now.

I really find this filter helps in my home. The only thing I can say is the companies idea these last over six months is insane. We don't smoke but have pets and this needs changing every 80-90 days. They are dark grey and cause the unit to run much louder by 90 days of use.

The Air Purifier is a great machine, small in size but puts out a strong volume of air. I put the machine on the top of the shelf just below the furnace and air conditioning vent that exits near the top of the ceiling above the bedroom door. Often times we have to reduce the airflow of the purifier to the lowest as it cools the room down too much during the night. Above all all it quiet on all 3 settings and makes it very nice to have on during the night when we are sleeping.

These replacement filters are just like the one installed in the Guardian AC4100 air purifier from the factory. Installation is easy, just snap off the rear cover. Notice the tab pull at the top and bottom of the installed filter. Applying a slight pull on the top tab will remove the complete filter. Since the prefilter will have dust attached be careful during removal. If you wish you can just wash out the prefilter, let it dry and reuse it. It is held to the HEPA filter with a couple pieces of velcro material. Remove the new FLT4100 filter from the box and cut open the plastic bag. Remove the complete filter and install it in the rear of the cleaner. Be sure it is installed with the prefilter (black) towards the rear cover of the unit. Install the filter cover and you're back in business. Process takes about 10 minutes or less.

These filters last for less time than they say they are supposed to. And, the charcoal filters are not as effective as some of the other brands available.
However, they do work well for about a month & 1/2.
Nowhere near the 6months as stated on their product information!
I've found that it does a much better job when I use their HEPA filter with another brand of charcoal filter.
If you are thinking of buying an air filter from Germguardian, I'd suggest that you buy one to two sizes larger than they recommend for small rooms.