Characterization of packaged superconducting parametric amplifiers via a complete set of scattering parameters in both the linear (S-parameters) and nonlinear (polyharmonic dispersion model, limited to the fundamental of the strong tone) regimes within the millikelvin temperature range and under probes composed of a few photon excitations. This includes the extrapolation of device-specific figures of merit, such as quality factor, gain, added noise, saturation, and compression points. RF measurements within the 4-12 GHz bandwidth and 20-900 mK temperature range. DC biasing lines are available. The devices should be connectorized (3.5 mm / SMA). Specific parameters for excitations, as well as necessary filtering and shielding requirements, will be discussed with the customer. In consultation, measurements requiring additional RF ports and pulsed microwave drives could be performed.