39579875 is an inlet check valve that was used on several older version of the Ingersoll Rand rotary screw air compressors. The check valve is a one way valve only letting air pass through in one direction.
This is an OEM part from Ingersoll Rand. IR used several different inlet valves over the years, please contact us with your model and serial number for confirmation 39579875 will work on your air compressor.
39588470
39907175
42412452
39236492