The NBS System 4 is a new Navigated Brain Stimulation (NBS) device for non-invasive direct cortical mapping in clinical neurosurgery as well as clinical research into applications of navigated rTMS. The NBS System 4 combines MRI-guided TMS with EMG measurement and incorporates DICOM export to surgical planning systems, surgical navigators and microscopes. Fully self-contained and mobile, the new system does not require a dedicated room or fixed installation and has a floor footprint of less than 0.6 m2. Nexstim has developed and implemented several proprietary features in the new system to enable NBS to be easily adopted as the routine solution for pre-surgical mapping of the cortex in clinical neurosurgery. Computer-aided alignment, motor threshold finding and E-field-based stimulation enable mapping of motor areas around a tumor in just 30 minutes - accurately and reliably. With the NexSpeech® module, the NBS also allows for the pre-surgical mapping of cortical speech areas. In post-stroke diagnostics, the powerful output of the stimulator is also a key feature enabling the clinical use of the NBS System 4 in determining the functional survival of muscle representation areas in the cortex and the integrity of sub-cortical motor tracts.