The 8481D diode power sensor measures average power over the frequency range 10 MHz to 18 GHz and power range -70 to -20 dBm (50 dB dynamic range). 
 The Keysight 11708A 30 dB attenuator is supplied with 8480 series power sensors with the "D" suffix, for calibration with the power meter 0 dBm, 50 MHz reference. 
 Key Features & Specifications: 
-  Excellent SWR for reducing mismatch uncertainty 
-  Accurate calibration and traceability to US National Institute of Standards and Technology (NIST) 
-  Compatible with EPM (new N1913A / 14A, E4418B / 19B), EPM-P (E4416A / 17A) and P-series (N1911A / 12A) power meters, plus the E1416A VXI and discontinued 70100A and 43X power meter 
-  Accurate average power measurements over -70 to -20 dBm 
-  Frequency range 10 MHz to 18 GHz 
-  Diode power sensing element