The 16380C is a standard capacitor set consisting of three precision capacitors - 0.01uF (16385A), 0.1uF (16386A), 1uF (16387A),and an optional 10uF (16388A). These capacitors are primarily used for performance tests of Keysight's 4-terminal pair LCR meters and impedance analyzers. Refer to the instrument's operation/service manual for the method of using these standards.