6680-00-053-3960 (S20)
6680-00-053-3960 is equivalent to manufacture part number S20. It is a sight plug and is classified under Federal Supply Class 6680 (6680 - Flow and Level Measuring Instruments), stocked for defense, aerospace, MRO, and industrial maintenance applications. This item is cataloged in the NATO supply system under 6680 - Flow and Level Measuring Instruments and is available through NSN-PARTS for U.S. government MRO, and commercial procurement.