A tachometer using solid state and/or vacuum tube circuitry.
NSN 6135-00-351-8606
NSN 5998-00-557-2832
NSN 6320-01-343-2482
NSN 5999-00-711-4491
NSN 6150-01-194-9517
NSN 6150-01-340-5493
NSN 6645-01-184-9142
NSN 5990-01-299-2014
NSN 6150-00-962-8622
NSN 5835-01-632-6627
NSN 6320-01-616-0843
NSN 6685-00-166-7281