For example: Agilent E4440A or Anritsu 68369
Termination
Anritsu 2000-1749-R
Low PIM Termination, 700 MHz to 2600 MHz, 10 W, 7/16 DIN(m), 7/16 DIN(f), 50O

Manufacturer: Anritsu
Bird Electronics 500-WT
500 Watt, WT Series Termaline® RF Coaxial Terminations

Manufacturer: Bird Electronics
Bird Electronics 8141
Termaline RF Coaxial Termination, Oil coiled, N Female, 250 Watt, DC-2500 MHz

Manufacturer: Bird Electronics