This extra Receiver Collar can be used to add another dog or as a replacement collar to the Wireless Pet Containment System (PIF-300-21) or the Stay + Play Wireless Fence (PIF17-13478). The collar features 5 adjustable levels of static correction or a tone-only mode to alert your pet with a beep. Over Stimulation Protection stops the stimulation after 30 seconds. Run Through Prevention will cause the static stimulation to increase if your pet tries to run through the boundary zone. This collar is for dogs 3.6kg & up and fits neck sizes 15-71cm. It's waterproof and has a low battery indicator.