Tracking device
Fans have long speculated that the Order was so easily able to follow Bree and Daniel because they were using a tracking device. This speculation appears to have been confirmed by Tachyon's message to Daniel.
Tracking Devices
Vehicle Tracking Devices
From Wikipedia: Vehicle Tracking Systems are electronic devices installed in vehicles to enable vehicle owners or third parties to track the location of a vehicle. Most modern vehicle tracking systems now use GPS modules to allow for easy and accurate location of the vehicle. Many systems also combine a communications component such as cellular or satellite transmitters to communicate the vehicle’s location to a remote user. Vehicle information can be viewed on electronic maps via the Internet or specialized software.
Non-Vehicle Tracking Devices
Tiny GPS based tracking devices, devised for covert tracking, are now available on the mass market. Commercially marketed devices can be as small as a small pager, weigh as little as a third of a pound, and have a battery life of nearly a month. Such a device could be planted in a person's pocket or belongings and used to track the person precisely and remotely over the internet. See example.
==Tracking Devices
