6625-00-793-1339 (FR175U)
NSN 6625-00-793-1339 (NIIN 00-793-1339) is a crystal calibrator in Federal Supply Class 6625, Electrical And Electronic Properties Measuring And Testing Instruments — a device primarily designed to determine by comparison the frequency characteristics of a piezoelectric crystal. Manufacturer part number FR175U (Joint Electronics Type Designation, CAGE 80058); also referenced as 111B (Meggitt (New Hampshire), Inc).
Key specs: 115 to 230 V AC voltage; 50 to 60 hertz frequency; full characteristics table below. NIIN assigned January 1962; DEMIL A (none required).