The QUANTUM DYNAMICS MCC-C-4(N) programmable counter applies user set multiplicative factors to four channels of input frequencies to translate said frequencies into engineering units with 6-digit accuracy . It is commonly used in jet engine test applications, such as T1 and T2 engine tachometer to RPM conversion, turbine meter frequency to flowrate conversion, direct measurement of frequency/vibration, etc.
The US Navy and US Air Force list the MCC-C-4(N) as NSN 4920-01-250-2775, while the US Army, and the U.S. Defense Logistics Agency list it as NSN 6625-01-556-0605.