Sorry.
I made what (may) be the same mistake the author may have.
I was referring to a stun gun. Hand held, lots of volts. Two electrodes...
If Zimmerman had had one, none of this would have happened.
Possibly, possibly not. Trayvon was on top of Zimmerman beating him up. For a hand-held stun gun to incapacitate the bad guy, you have to hold it continually against him for several seconds, per the manufacturer . This implies that you have the ability to pin him down long enough. Zimmerman didn't. Stun guns are for use by police to subdue a bad guy and get him to submit to being cuffed, and are generally used when the police side has enough physical force to pin the guy long enough for the stun gun to work.