Tracer E-collar Light - BlueRemotely activated by your Tri Tronics transmitter. The Tracer is a lightweight, very brilliant, LED light device that lets you know where your dog is after dark. It is available in white, red, or blue and has a choice of two light modes blinking or steady. By using differing combinations of light color and mode, you can identify multiple dogs. In addition, you can leave it on as long as required or switch it on only when needed.