or maybe a better question is what is it used for?

 

You push the button and the battery explodes. Usually used for when ricers won't stay away from your car when the hood is up.



It's just a switch that lets you disconnect the battery from the car so it cannot be stolen.

 

disconnect for the battery..usually to prevent theft

and designed to completely shut the charging in an emergency situation

 

if you go drag race @ the tracks, some of them won't let you run with a relocated battery unless you have an external killswitch

 

makes sense thanks fellas

 

they are both right Its good for anti theft..but they are required on cars that hit a certain et..and lower...its in the nhra rule book...if you don't have it you can't run...its a safty precaution incase something happens like a fuel leak or something they can shut down your car before something happens