Seems to be a good quality filter. I've been running mine for 10 months in a bloom only tent. On the 4th harvest with this filter I could smell outside pretty good before the chop. So I think I'm going to have to replace this before I'm ready for the next harvest. Many other users claim they have gotten 18+ months out of this filter so this is why I only give 4 stars. However, it could be that others are using this for veg and bloom where as I am only using it for bloom thus filtering a much stronger odor more often.
I used Vivosun & iPower filters before this and the Hon&Guan is much better. I got many defective units or ones that wouldn't even last six months with the other brands. The Hon&Guan isn't much more expensive and is worth it for sure.