6645-00-138-7997 (567AS2200)
6645-00-138-7997 is equivalent to manufacture part number 551AMB-5. It is a fixed mounting mechanical tachometer and is classified under Federal Supply Class 6645 (6645 - Time Measuring Instruments), stocked for defense, aerospace, MRO, and industrial maintenance applications. This item is cataloged in the NATO supply system under 6645 - Time Measuring Instruments and is available through NSN-PARTS for U.S. government MRO, and commercial procurement.