| OCXO Precision Frequency Reference | R&S®FSW-B4 |
| Resolution Bandwidth > 10 MHz | R&S®FSW-B8 |
| Resolution Bandwidth > 10 MHz | R&S®FSW-B8 |
| Highpass Filter for Harmonic Measurements | R&S®FSW-B13 |
| Digital Baseband Interface | R&S®FSW-B17 |
| Spare Solid State Drive (removable hard drive) | R&S®FSW-B18 |
| LO/IF connections for external mixers | R&S®FSW-B21 |
| RF Preamplifier, 100 kHz to 13.6 GHz | R&S®FSW-B24 |
| RF Preamplifier, 100 kHz to 26.5 GHz | R&S®FSW-B24 |
| RF Preamplifier, 100 kHz to 43.5 GHz | R&S®FSW-B24 |
| Electronic Attenuator, 1 dB steps | R&S®FSW-B25 |
| USB Mass Memory Write Protection | R&S®FSW-B33 |
| 28 MHz Analysis Bandwidth | R&S®FSW-B28 |
| 40 MHz Analysis Bandwidth | R&S®FSW-B40 |
| 80 MHz Analysis Bandwidth | R&S®FSW-B80 |
| 160 MHz Analysis Bandwidth | R&S®FSW-B160 |
| Analog Baseband Inputs,40 MHz Analysis Bandwidth | R&S®FSW-B71 |
| Analog Baseband Inputs, 40 MHz Analysis Bandwidth | R&S®FSW-B71 |
| 80 MHz Analysis Bandwidth for Analog Baseband Inputs | R&S®FSW-B71E |