What can you tell me about civilian-grade tasers?

Last night, I went to a sporting goods store in order to do a little research on small, folding knives because I want to pick one up for protection. Later, I spoke to a friend of mine about this and he told me that not only would a knife not really deter anyone who was intent on hurting me, but it was very likely that a big guy could get the knife away from me and I could be legally in the wrong for pulling a knife on someone, even if I feel threatened. These seem like pretty cogent arguments to me. I discussed taking self-defense classes and he suggested I invest in a civilian-grade taser. They are effective at incapacitating even large assailants and I would not be legally in the wrong for using one. However, they are ridiculously expensive so I’ve decided to do a lot of research before I buy one.

Naturally, my first stop on Research Road is Jelly Central in Fluther City. Will you fine Jellies help me start my research?