Can ULNF and LNF be used with the B2901/02/11/12A?

No. Using these optional filters with the Keysight B2901/02/11/12A SMUs is not recommended.

There are two optional filters for the B2961/62A. One is the Ultra Low Noise Filter (ULNF) and the other one is the Low Noise Filter (LNF).
The Keysight B2961/62A and both filters are designed to show their best performance only when they are used with together.
If the filters are used with the Keysight B2901/02/11/12A, the following problems will occur.
- Both filters possibly show large overshoot on the signal, which may damage the devices or degrade the performance.
- Both filters possibly increase noise on the signal at some specific frequencies and you may not be able to obtain noise fitering.
- Both filters make the B2901/02/11/12A degrade their current measurement performance.
- The B2901/02/11/12A may damage the ULNF, because the B2901/02/11/12A doesn't have the function to limit the output range supported by the B2961/62A with the optional filters.

Therefore using these optional filters with the Keysight B2901/02/11/12A SMUs is not recommended.