Any large overbuilt metal pen will do the trick . Of the ones I have seen , the Tuff Writer is among the most practical . The Benchmade is too overtly weaponized , most instantly recognize it for what it is . The Timberline isn't too bad . I will probably get the Surefire iteration when they come out .
A word about application , KISS ! Much Kabotam methadology is aimed at LEO's and involves restraints and comealong appilications . Civilians have no duty to try and arrest or restrain , ignore these methods and look for simple demolition . Stick with simple gross motor hammerfist moves , the head and face , back of hands etc are prime targets . Basically hit all the spots proscribed in the LE oriented manuals ( kidneys , nads , eyes etc.)
Many of the same moves transfer readily to flashlights , sharpie markers , any short stick immitation .
Chris