Review on 🐶 3-in-1 OYEFLY Handheld Dog Trainer with LED Flashlight and Bark Stopper - Training Tool to Stop Barking (Gray) by Marc Gallner

Cheaply made, but inexpensive and effective. Dogs can definitely hear unless they are deaf 😂. Its effectiveness depends on how you use it to train your dog. There are medium settings just to get their attention or to suggest specific commands to be taught, and high or intimidating settings that will startle some dogs. I have successfully used the high setting to break the bad habit of the incessant barking of my three small pet terriers who used to bark a lot at visitors and guests. No longer. The size isn't small enough to carry in a bag all the time, but it fits in a jacket pocket for occasional use, sort of like a TV remote control. Require a 9V battery, not included. It also has a flashlight function without a sound signal. I think it can be used for visual training if that works for you and your pet. Cats can hear it too, but good luck learning 😂