Dog whistle with the dog (can also be used for other pet birds such as pigeons) to establish a good tool for communication and discipline. While using this product can produce ultrasound and spread very far. Within 3 km can be heard. Dog whistle will send a dog can detect ultrasound. New Pet Training Dog Adjustable UltraSonic Sound Whistle. This is Pet Training Dog Adjustable UltraSonic Sound Whistle. Ear of dog to receive sound waves per second, 120 kHz, while the people can hear up to 20 kHz. Dog whistle can be issued in addition to the human voice can be heard outside the tube, while the sound people hear is, only dogs can hear frequencies, this frequency ultrasound transmission is very far, so the dog can be very far away hear the sound. The sound can be heard by human as well . please don\&39;t worry This Whistle can help you to train your dogs. Original box: NO Item size: 55*7mm Net weight: 16g color:silver Each 100pcs in a opp bag package |