This MERV-8 filter is for use with Seaira Watchdog 550 dehumidifiers. It sits behind the pre-filter on your Watchdog Dehumidifier. The purpose of a MERV-8 filter is to help remove dirt and dust particles from the air. A MERV8 filter comes standard with your unit. It is recommended that the filter be changed about once a year. It is not washable.
The W-517 comes in a 3 pack. Actual product may differ from photo. The Watchdog 550 filters are more rectangular.