Compatible with: Sentinel HD90/Sentinel HDi90 Dehumidifier MERV-8 filter captures the majority of “larger” airborne particles after the air blew into the machine. It can protect the inner component from the congestion of impurities from the air taken in from the outside. Dimensions: 11.8 × 9.9 × 0.4 inch Also at the same time ensure the maximum airflow supply volume 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).