It can be hung on a tree, indoor, outdoor wall or fence to prevent dogs from barking (within range). -Ultrasonic waves are harmless to pets and can not be heard by human ears, so the device can be used safely.
eBay
Dog Bark Deterrent Device Long-Range Ultrasonic Anti Barking Device Stop Dogs Bad Behavior
Aliexpress UK
[Easy to carry]-The ergonomic design is very suitable for your hands, and the climbing buckle and hand rope can let you carry this ultrasonic dog barker anywhere. [High Power]-20Khz-25Khz irregular frequency sound waves can effectively prevent dogs from adapting to specific ultrasonic frequencies, thereby improving the effect of use.Powerful dual sonar heads has higher power and more effective than the single head on the market.
eBay
Mini Ultrasonic Dog Repeller Training Dog Stop Barking Smart Portable Outdoor Defense Dogs
Aliexpress UK
The anti-barking device is great for stopping neighbour's dogs or any dogs at all barking near your house! Ultrasonic dog training is safe and effective for all types and sizes (5-120 lbs)of dogs. Suitable for dogs from 6 months to 8 years.
eBay
2 In 1 Training & Anti Barking Device Ultrasonic Dog Repeller With Flashlight Stop Attack
Aliexpress UK
Features:-It adopts a dog barking sensor system, which can accurately detect dog barking, safe for pets, and then automatically emits ultrasonic waves to stop the dog from barking.-With 3 different frequencies, the 15-30kHz frequency can prevent large dogs from barking at a distance of 15m, the 20kHz frequency can prevent medium-sized and docile dogs from barking at a distance of 10m, and the 30kHz frequency can prevent small dogs from barking at a distance of 5m.-With a wide effective range of 33 feet, it can be easily placed on tables, shelves, windowsills, etc., hung on trees, walls, fence posts, etc.-Equipped with a 1800mAh high-performance battery, it only takes 2 hours to fully charge and can be in standby mode for up to 30 days.-With LED light to show.
eBay
Ultrasonic Dog Repeller Anti Barking Device USB Rechargeable & Portable Dog Trainer with LED Light
Aliexpress UK
Stop nuisance dog barking quickly & easily. Train and stop any dog from nuisance barking. Mini Dog Barking Anti Bark Collar Ultrasonic New. Collar sends out an ultrasonic signal that only dogs can hear.
eBay
Outdoor Ultrasonic Bark Arrester |3-speed Adjustable Anti Barking and Dog Repelling Device | 5-meter
Aliexpress UK
With 4 ultrasound heads. to form a conditioned reflex. The principle of a bark stop device is that when the dog barks, ultrasound will work. 【3 Adjustable Ultrasonic Levels 】Features three adjustable ultrasonic levels (10-16KHz for small dogs;. ).
eBay
1pc Dog Repeller LED Ultrasonic From Dogs Anti Barking Device Laser Dog Repeller Training Device
Aliexpress UK
Used to prevent dog attacks, issue ultrasound to repel the dog or wild wolf. This product adopts double channel enhanced, double dog training, excitation drive dogs, function is one of the super ultrasonic.
eBay
Portable Dog Repeller Anti Barking Stop Bark Training Device Trainer LED Ultrasonic Multifunction
Aliexpress UK
The trainer is based on the theory that ultrasound (ultrasonic wave reaches up to 125db) is above the upper limit of human hearing and super ultrasonic and 28000mcd strong white light. There are three modes for use: Training dog, Banish dog, Illuminating.
eBay
Ultrasonic Pet Dog Repeller Anti Barking Stop Bark Training Device High Power Dog Training
Aliexpress UK