Reference usaf dwg 56b23624, for special markings
A tachometer that is driven through the media of a mechanical connection and includes provisions for fixed mounting.
NSN 6240-01-095-5421
NSN 2925-01-446-6976
NSN 6320-01-422-1212
NSN 6220-01-498-7211
NSN 5950-01-592-3145
NSN 6320-00-925-0558
NSN 5999-01-368-9624
NSN 6145-01-043-5992
NSN 5990-00-477-1362
NSN 5935-00-983-6947
NSN 6685-01-283-7960
NSN 6650-00-465-7654