Humanization Hand-Carry DesignDesign with anti-mistake lock and LED light to use at the dark place and in the evening, potable anti-barking device comes with humanization contour to hold. It is delight design and suitable for indoor and outdoor use! Note: when the button light indicator turns be red, it means this product is in low power situation. Repellent ModeEmit a higher intensity ultrasonic sound while with the flashlight flashing to drive the fierce dog away, such as stop excessive barking, fighting, biting, and other bad behaviors. Training Repellent ModesTraining mode: emit a lower intensity ultrasonic sound to assist you correct dog's bad behaviors and to teach it how to be polite act and training their brain to become smart pet in our daily life. Up to 25FT Range EffectivelyThe working range is 25FT, the device getting closer and closer with the dog , the device will work nicer, effective pet corrector for dogs of all types and sizes of age 6 months to 8 years old. Dual Sensor Anti Barking DeviceSafe and efficient dog barking control can emits an ultrasound of 20 25 KHZ, which will make barking dogs become quiet and less aggressive, and you and your kids will not be afraid of this situation anymore. This anti barking device with dual heads has higher power and more effective than other device which has single head only,this electronic dog whistle equips with 800mah rechargeable battery,provide full charge about 3 hours and can be used about 30 days.