Top quality Kesav Mehudar with Batim Perudos (Batim Shel Rosh are completely seperated). Kesav Chabad is basically the same as Kesav Arizal, but unique in style. The Batim are also much larger in size. If one insists on Kesav Chabad, only top quality is recommended. Cheap Chabad Tefillin & Mezuzahs tend to have many problems.