The ICEdot Crash Sensor detects life threatening impacts and sends an emergency message through your smartphone to someone who can get you medical help. When an incident happens, the ICEdot sends a Bluetooth signal to an app on your smartphone. An alarm will sound on the phone, giving you a chance to stop the distress signal from going out if you're ok. If you don't stop the app, it sends an SMS text message to your pre specified emergency contacts with your GPS coordinates. Proposition 65 Warning for California Consumers: This product contains chemicals known to the State of California to cause cancer andor birth defects or other reproductive harm.