From the day they are new, attenuators are all slightly different due to manufacturing tolerances. We test attenuators using a vector network analyser, calibrated by the 12-term correction method. This method eliminates the inacuracies associated with source and load mismatch, giving the most reliable and consistent readings possible. We sweep the test frequency over a wide range, and capture all of the measurement data, which is then supplied with the attenuator.

This attenuator is in excellent "used" condition. Please view the measurement data, and HP technical manual.