The PetSafe wireless dog fence receiver is designed to comfortably fit your dog with a curved inside edge and two sets of probes to ensure the best fit for your dog. The receiver is waterproof and has a low battery indicator light that will blink to let you know it is time to change your battery. The wireless fence receiver has built in over correction protection, it will automatically shut down if your dog leaves your yard. The receiver is lightweight weighing only 2.5 ounces.