The great thing about our training tools is they are designed to not be heard by humans. This does lead to the commonly asked question: “How do I know the ultrasonic sound is being emitted?” This is a great question!
There's a pretty simple sound test you can do that we refer to as the “Lighter Test.” Sound, even ultrasonic sound, moves the air around it. We cannot feel this movement, but we can see it when a flame is held in front of it.
To perform the test, hold a lighter up to the end of the OnGuard™ that emits sound, light the flame and push the sound button at the same time, and see if the flame bends. If it does, you have ultrasonic sound being emitted. Super simple :)