6625-00-255-5841 (P400M101)
NSN 6625-00-255-5841 (NIIN 00-255-5841) is an electrical frequency meter in Federal Supply Class 6625, Electrical And Electronic Properties Measuring And Testing Instruments — an instrument which measures the rate of regularly recurring variations in an electric current or voltage and is usually calibrated in hertz (cycles per second. Manufacturer part number P400M101 (Iet Labs Inc, CAGE 62015); also referenced as P400-1 (Iet Labs Inc).
Key specs: zero adjuster; 0 to 20 kHz frequency response range; full characteristics table below. NIIN assigned January 1963; DEMIL A (none required); unit of issue EA (each), $111.86 gov standard price; export Schedule B 9030.90.8030.