About this item DIMENSION:12.6 x 10.1 x 0.4in, compatible with Sentinel HD90/Sentinel HDi90 basement dehumidifier with production date after April 18, 2022.Note: The difference between the new version and the old version is that the new version adds four screw holes. And the Serial Number before S39037 are the older models (e.g. S39036), the Serial Number after S39037 are the new models (e.g. S39038). It can protect the inner component from the congestion of impurities from the air taking in from outside. Also at the same time ensure the maximum airflow supply volume. EASY & SIMPLE TO USE: Installing or replacing our air filter is easy. Simply slide the filter into the air filter return of your unit and you're done! It is recommended that replace your air filter every 90 days or 3 months, make your air quality healthier.