Kaz Online Store
This round wicking filter from Protec is a replacement humidifier filter. These can be used with Vicks Cool Mist models such as: V3100, V3500, V3600, V3700, V3900, and others. It can also be used with Kaz HealthMist Model 3020.
Are you looking to buy more than one?
Information about the V3100
For the V3100, you will "flatten" the filter out. If you examine your original filter you will see that it, too, is a round filter.