This MERV 10 filter is for use with all NXT dehumidifiers. It sits behind the pre-filter on your Watchdog Crawl Space Dehumidifier. The purpose of a MERV-10 filter is to help remove dirt and dust particles from the air. A MERV10 filter comes standard with your unit. It is recommended that the filter be changed about once a year. It is not washable.
The N-201 comes in a 3 pack.