“Normal people only can hear the range of sound from 20Hz up to 20KHz. Dog [sic] can hear much wider range,” the press release tells us.
Therefore, an ultrasonic device producing sound at a frequency higher than 20KHz can work to train dogswithout being heard by us humans.
“It not only suitable for pets but also police dog and shepherd,” the press release continues in its broken English, before adding: “This portable device also good for expel ferocious dogs. That is why this device also purchase by all those people who live next or pass by with ferocious dogs.”
Not got a problem with dogs yet? Use it as a handheld LED torch until you do…
Specifications include:
* Handy strap for easy carrying
* Dimensions: 12.5cm x 4cm x 2.7cm
* Powered by 9V battery
* Colour: Yellow.