Whats the best thief protection device available?

[LxMustangRacer]

There's this anti-theft device called the auto taser. Basically it's a cross between a taser and a club. It locks onto your steering wheel and looks basically the same as a club, the only difference being when you touch it you get shocked as if someone hit you with a stun gun(I don't think it's as powerful). I really don't hear much about them and have no idea how well they really work. I gotta say though, the though of someone attempting to steal your car getting shocked is very appealing.