This pre-filter is for use with NXT120 and NXT120C dehumidifiers. It attaches to the inlet end of the dehumidifier directly in front of the regular filter. The purpose of the pre-filter is to help remove particles from the air before they hit the main filter. The pre-filter can be vacuumed and is washable as well. A pre-filter is included with your Watchdog dehumidifier. This is a replacement pack.
The N-1200 comes in a 3 pack.