【Level 3 Operation】The frequency-adjustable dog barking deterrent is suitable for various dogs. 15KHZ-30KHZ is suitable for large, mischievous dogs. 20KHZ is suitable for obedient dogs. 30KHZ is suitable for small dogs. Recommended for dogs aged 6 months to 8 years. 【Safe and Easy to Use Dog Training】The dog barking device can prevent dogs from barking safely and gently. When he reacts positively, praising and rewarding him improves his memory. Continuous training is required for effective and lasting results. 【Easy to Install and Waterproof】You can hang the dog silencer on a tree, wall, or fence to prevent your own or your neighbor's dog from barking. Make sure the barking controller is facing the dog within range without any obstructions. 【Rechargeable Barking Prevention Device】Built-in rechargeable lithium battery for ultrasonic dog drive, can be used continuously for 30 days with a full charge of 5 hours. Red/Blue indicates the battery status.