Do the PRO line systems have any built-in / hardware filters?

No, all recorded data remains in its raw form. The Windows and mobile applications offer the ability to apply band-pass filtering to EEG data within the range of 1Hz to 40Hz, but this feature is strictly for visualization purposes. Regardless of whether the filter is active, the EEG data continues to be recorded in its raw state on your PC, phone, or device memory.