A tachometer using solid state and/or vacuum tube circuitry.
NSN 5925-00-300-3216
NSN 5920-00-258-6822
NSN 5895-00-398-0029
NSN 5985-01-134-0461
NSN 5965-01-385-7813
NSN 5985-01-587-6045
NSN 5975-01-106-2941
NSN 6620-01-499-1492
NSN 6240-01-202-3179
NSN 5999-00-631-4382
NSN 6135-01-487-6275
NSN 6610-01-600-5789