The Keysight 41800A is an active probe with high input impedance that covers a frequency range from 5 Hz to 500 MHz. It is ideal for precise in-circuit measurements in audio, video, RF and VHF circuits, as its low input capacitance of 3 pF places hardly any load on the circuit. With an input resistance of 100 kΩ and an output via a 50 Ω type N connector, it is compatible with various Keysight spectrum and network analyzers. In addition, the probe has a retractable metal protective cover that protects the tip from mechanical damage and electrostatic discharge (ESD).