A tachometer using solid state and/or vacuum tube circuitry.
NSN 6650-00-172-7519
NSN 6135-01-627-3786
NSN 6220-01-189-4112
NSN 6650-01-174-5788
NSN 6685-01-076-4703
NSN 5960-01-215-0992
NSN 7035-01-505-5399
NSN 4140-01-650-6367
NSN 6105-01-470-9956
NSN 5999-01-225-5720
NSN 5965-01-070-9265
NSN 5905-01-098-9780