Embarrassingly, I had no idea my vacuum had a large filter that needed replacing. For the past two years I've been very frustrated that my vacuum cleaner, which I thought was expensive, wasn't working very well, and when two dogs vacuumed the same spot multiple times just to keep the carpet looking decent, it was exceedingly annoying. After looking for a small triangular filter, I was surprised to see that this wasn't the only filter involved. I still feel like an idiot but after installing these new filters my vacuum is like new. I am so happy with the results!