The 16380A is a standard capacitor set consisting of four precision capacitors - 1pF (16381A), 10pF (16382A) 100pF (16383A), 1000pF (16384A). These capacitors are primarily used for performance tests of Agilent's 4-terminal pair LCR meters and impedance analyzers. Refer to the instrument's operation/service manual for the method of using these standards.