The 8485D diode power sensor measures power over a frequency range from 50 MHz to 26.5 GHz and over a power range from -70 to -20 dBm, a dynamic range of 50 dB. The 30 dB attenuator 11708A is used together with the power sensor series 8480 included, this attenuator has a "D" mark. The label indicates that it can be used for calibration purposes in conjunction with the power meters and a 50 MHz reference source.