They're safe for dogs 5-120 lbs, from 6 months to 8 years old. The ergonomic design fits nicely in your hand, while a carabiner lets you take this ultrasonic dog bark deterrent anywhere. It has sound and ultrasonic modes with a frequency of 25 kHz that's hard for humans to hear.
eBay
Can be hung on trees, indoor, outdoor walls or fences to prevent dogs from barking (in range). Ultrasonic anti-barking device can automatically detect dog barking from 50 feet away. There are 4 frequencies for ultrasonic waves to choose from.
eBay
NEIGHBORS DOG SILENCER: Dog silencer captures barking in the area covered by the system, solving the problem of excessive barking and stopping your own dog or your neighbor's barking. WATERPROOF AND DURABLE: Barking box is made of ABS material, waterproof and durable, can withstand all kinds of weather conditions, and is a great choice for dogs to stop barking outdoors.
eBay
Anti-bark Muzzle Basket Muzzle Cat Mouth Mask Muzzle for Cat Outdoor Muzzle. Dog Whistle to Stop Barking Whistles for Recall Deterrent Devices. 2 PCS Dog Training Silent Anti Barking Device Deterrent.
eBay
Stop Unwanted Barking Without Harm,this anti barking device for dogs emits a 25 kHz frequency (inaudible to humans) to gently correct dog behavior. Ideal for training puppies to adult dogs while protecting their sensitive hearing.
eBay
Keep your dog well-behaved with thisUltrasonic Dog Trainer. Safe, effective, and easy to use, it emits a high-frequency soundinaudible to humans but heard by dogs to discourage unwanted behaviors like excessive barking.
eBay
Super -ultrasonischer Antrieb mit einem doppelten Kanal gebogene Rille kann für Hundetraining, lasergetriebene Schlange, Katzen fahren und beleuchtet werden. Farbe: Schwarz. Super-Ultrasonic-Antrieb mit einem doppelten Kanal gebogen.
eBay
Can be hung on a tree, indoor, or outdoor wall, or fence to prevent dog barking (within range). An ultrasonic anti-barking device can automatically detect dog barks 50 feet away. New 3 Way Switch Pickup Selector Toggle For Les Paul Epiphone Electric Guitar.
eBay