This extra Receiver Collar can be used to add another dog to any PetSafe In-Ground Fence system or as a replacement collar to the Stubborn Dog In-Ground Fence System. The collar features 5 adjustable levels of static correction or a tone with vibration mode to alert your pet with a beep. Over Stimulation Protection stops the stimulation after 30 seconds. Ideal for stubborn or hard-to-train dogs, it will cover up to 1/3 acre with included boundary wire. This collar is for dogs 3.6kg & up and fits neck sizes 15-71cm. It's waterproof and has a low battery indicator.