Critcal due to fit requirments.
An item that can generate a fundamental frequency with a high degree of accuracy. Harmonics of this fundamental are then used as a reference point for checking throughout the radio spectrum. The standard may be stable crystal oscillator, noncrystal oscillator, tuning fork, atomic beam, molecular beam, gas cell, quantum mechanical resonator, or the like.
Classification: Parts and accessories of articles of schedule b subheading 9030.39
NSN 5910-01-098-2081
NSN 5990-01-303-6110
NSN 5910-01-056-2166
NSN 6150-00-144-7115
NSN 6320-00-593-0379
NSN 5915-01-599-1266
NSN 6130-01-560-0113
NSN 6145-00-155-5297
NSN 5945-00-199-5681
NSN 5999-00-578-5658
NSN 5925-01-584-5331
NSN 4140-00-501-7833