This extra Stubborn Dog Receiver Collar can be used to add another dog or as a replacement collar to the Stay + Play Wireless Fence™ or Wireless Pet Containment System. Features For dogs 2.3 kg and up Fits neck sizes 15 - 58 cm For stubborn or hard-to-train dogs Tone-only mode alerts your pet with a beep 5 adjustable levels of static stimulation Over Stimulation Protection: Stimulation stops after 15 seconds Waterproof Uses a rechargeable battery Each charge usually lasts 3 weeks Battery recharges in 2-3 hours Low battery indicator Compatible with the Stay + Play Wireless Fence™ or Wireless Pet Containment™ System (PIF-300-21)