For example: Agilent E4440A or Anritsu 68369
Filter
Passive or active filters
Keysight / Agilent 08360-60016
Power Supply Rectifier Filter Assembly
Manufacturer: Keysight / Agilent
Keysight / Agilent 08360-60017
Power Supply Rectifier Filter Assembly
Manufacturer: Keysight / Agilent
Keysight / Agilent 11694A
3 MHz to 500 MHz,75 Ohms Matching Transformer
Manufacturer: Keysight / Agilent
Krohn-Hite 3202
Krohn-Hite 3202 Dual Channel Solid State Variable Filter, 2 MHz
Manufacturer: Krohn-Hite
K&L Microwave 3TNF-200/400-N/N
3TNF-200/400-N/N Tunable Bandreject (Notch) Filter
Manufacturer: K&L Microwave
Stanford Research Systems SR645
Dual High Pass Programmable Filter
Manufacturer: Stanford Research Systems