It was $120 + S&H, and the microwave sensor was supposed to be an extra $20, but it was sent with mine anyway, accident? Not sure. And it recognizes the hands free by getting a signal from the remote, if "AUTO" is on and you have the keys with the remote in your pocket, when you get within 3-10 meters of the vehicle it disarms the alarm and unlocks the doors. It does the same to Arm it, once you shut all the doors it waits 5 seconds and as long as the remote is out of the 3-10m range it arms the vehicle and rolls up the windows if its set up that way. Its a pretty cool setup. Has tons of other features like anti-hyjacking mode and all kinds of stuff.