Thank you for viewing my item!    Available is a vintage HP Wave Analyzer.    It is for the model 3581A.    It is missing the push button for the volts, otherwise looks to be complete and in good used physical condition.   The item powers on and does display a reading.    The reading did change as we adjusted some of the buttons.    The case measures approximately 15 1/2 x 11 inches.   Shipping will be UPS ground charges on 35 pounds in the US.    There will be no international shipping on this item.