The TELETrak Pet Tracking System consists of the transmitter (DC 20) and the user's handheld receiver (TT 220). The DC 20 is mounted directly onto a standard one-inch collar so that the unit fits on the back of the pet's neck. The system shows the precise direction and distance to your pet, indicating if it is running, sitting, or in pursuit. It can track up to ten pets per receiver at once, and location-updates can be as often as every five seconds.