StenchX PlusPet Active Carbon Pre-Filter 4-Pack (AC4825 filter) for use with the GermGuardian FLT4825 HEPA Filter, Filter B. Premium AC4825 Series Replacement Filter with AllerBlockX Technology

Some reviews have said it has no velcrow which is true, but so long as at least one bit stays on your filter's frame it doesn't matter. The random mesh is much better, being denser, than the prefilter that came with either of my other main stage filters, and since they are folded in the package if so much as one of the teeth sided velcrow stays on the frame, the bend will hold it in place until the backing is reattached.

I love these filters! I love my germ guardian! I have an asthmatic,allergic, eczema ridden teenager. Did I mention he's an active boy? I tried the germ guardian along with a dehumidifier last year because his dorm room was very humid and contained carpet. He's suffered with this since birth so we removed all carpet and all other allergen triggers (shrubbery, certain chemical cleaning products in his space, etc) at home. After installing the two devices on campus, he didn't have any asthma attacks and his allergy symptoms remained at bay with his regular meds. As a mom, with a child away for the first year, this was wonderful. Good news right? But here's the best surprise of all! When he came home this summer he bought the germ guardian home and turned it on. Not only does it picks up particle triggers in the air, it actually helps neutralize the feet fragrance in the room! God is good and merciful to this old girl living in a house full of men!! I'm truly thankful, you have no idea!

I did not like the quality of these compared to my original filters

These arrived as expected. They are fantastic. Thank you

Works perfect

Pre filter is working great. If used properly it will save the life of the more expensive filter.

Doubles the life of my primary filter and easy to replace.

Everything went perfectly