Fred Perrin is a master of self defense items that are worked into EDC situations. If you dont know who Mr. Perrin is, just Google him and you will find tons if info on him.
Here is a video of his bracelets and how they work:http://szaboinc.com/bracelets.html
(I stole this video from "Death's Head, thanks buddy!) You need to watch the whole video to see how they work.
Here is my EDC Perrin bracelet that I just got stone washed to tone down the bling a little bit:
Here is what it looked like before being stone washed: