These are switches that are covertly hidden somewhere on your vehicle. In order to start your vehicle, you have to turn on the hidden switch. In order for kill switches to be effective you have to always remember to turn off the switch when you get out of your car.
Kill switches are usually custom installed by specialty shops and should be professionally installed in order to ‘blend in’ with the factory wiring.
PowerLock - Power start switch.
Ravelco - This is not a kill switch but rather a special plug you put into a covertly hidden socket. In order to start the vehicle, you have to insert the plug into the socket. As secure as this is, the drawback is having to carry your car key as well as the plug.
Master Lock Starter Sentry - A plug in the fuse box with a proximity sensor module for your keychain. Cannot find a website for this. The one I had is a broken link.