From Amazon come these reviews:
>> This product does nothing that I can see, the dog does not respond to the whistle.My dog appears to not notice this whistle,and it takes a lot of pulling to get it to whistle and is not at all loud.
>> Put it on my dog to take her to the dogpark and before we got in the gate it fell apart and my dog was off on her own. Thankfully was able to get her before she got to far, but this item is a piece of junk. Not recommended.
>> Product make a low short tweet like whistle it does not stop the dog from pullng and does not distract the dog at all.
>> The Tweeter was the worst 10 pounds I ever spent. Completely useless. Hardly any noise comes out of that thing, and if my dog doesn't pull suddenly, there is no noise at all. Whatever 'tweet' it makes, doesn't bother my dog. She doesn't even hear it. Whatever you do, do NOT waste your money on this thing.
There's no reason to buy a "Dog Tweeter" training aid when I will sell you