Plot accurate antenna patterns -- connect between your receiver and antenna and use your S-meter as a precision calibrated field strength meter.
This will be your most useful hamshack accessory. Ideal for fox hunting.
Determine gain, loss and to evaluate linearity of circuits. measure input and output level differences.
Isolate one circuit from another. Extend the range of sensitive measuring equipment, and much more. Up to 81 dB attenuation in 1 dB steps. 250 mW maximum input. Sturdy, black all metal cabinet.