dogs were interested in the whistle at close range...I paired the whistle with a reward with the intent of using the whistle for a recall, I then built up distance
WELL turns out the dog aren't hearing anything but the air excaping the whistle, so once they were 10-15 feet away the thing was useless since they could no longer hear it.
fun to watch them cock their heads, but useless for training...I have since started using a normal whistle with great success.Get more detail about SportDog European-Style Silent Whistle.