Overview of DVD PART TWO – Categories Presentation. NST DVD PART TWO. is a two hour long instructional DVD of the Categories work and shows just how easy it is to integrate additional work for the Upper Extremity, Lower Extremity, Thoracic area, Central Base and Cranium into the Core itself. Note: DVD Part Two summarises three and a half days of actual workshop content. See sample intro video: http://www.vimeo.com/2368181