PetSafe Ultrasonic Remote Trainer for Dogs and Cats Uses ultrasonic sound to teach commands and correct behavior 30 foot range is best for indoors and small outdoor spaces Positive and negative tones for training flexibility Suitable for dogs and cats of any size, 6 months and older No Bark Guarantee: Some dogs may not be responsive to ultrasonic correction. If this product is not meeting your needs, please contact PetSafe Brand. Call, chat or email the PetSafe US-based customer care specialists six days a week