Product review (4 stars): Stock up on these if you're using your Vornado humidifier a lot!
If you have the Vornado humidifier that this fits, you'll want to stock up on these.

Since the humidifier can sometimes cut off (power surge) or timer/sensor, the wick can get "funky" since you're supposed to keep the evaporation/airflow going pretty constantly to prevent mold/mildew build up.

It's hard to just let the humidifier just run constantly, so when it's not needed for awhile, we throw away the old filters and insert new ones.  It seems expensive considering what it is, but they are a necessity.