6630-00-975-6971 (11-556-12)
6630-00-975-6971 is equivalent to manufacture part number 11-556-12. It is a graduated scale hydrometer and is classified under Federal Supply Class 6630 (6630 - Chemical Analysis Instruments), stocked for defense, aerospace, MRO, and industrial maintenance applications. This item is cataloged in the NATO supply system under 6630 - Chemical Analysis Instruments and is available through NSN-PARTS for U.S. government MRO, and commercial procurement.