• Ultrasonic anti-barking device with improved 4-hole design for greater effectiveness. • Features 3 adjustable ultrasonic wave frequencies to adapt to different needs. • Effective range of up to 33 feet (10 meters) to automatically stop barking. • Rechargeable battery with up to 30 days of continuous use and 60 days of standby time. • IPX4 waterproof design suitable for both indoor and outdoor use. • Safe and humane method for training small and large dogs. • Intelligent operation that automatically detects barking to activate ultrasound.