Genuine ACME ‘silent’ dog training whistle no. 535. Adjustable frequency. Good sound quality. Weather-proof. Designed and made in the UK. Solid brass with nickel plated finish

I’m really not sure what all of the consumers who rated this whistle poorly were expecting, but they obviously weren’t expecting anything realistic. This Acme Whistle #535 is a top-of-the-line training tool used most commonly with dogs, but is also the same bridge whistle used in training many marine mammals (such as dolphins and orca/killer whales) in several facilities all over the world.There is no such thing as a miracle product. With that said, there is nothing in the product description that claims that this is either a whistle to “annoy” a dog, a whistle make a dog stop barking, nor is the tool actually silent. There is no such thing as a silent training whistle; that defeats the purpose of its use. It clearly explains that this whistle is extremely high-pitched (with the option to adjust the frequency) and can be *almost* inaudible to human ears. In other words, it’s not startlingly loud and irritating to us, but you can still hear it.For those of who who expect the Acme Silent Dog Whistle #535 to miraculously work immediately, you need to understand that nothing you do will have instantaneous results. This whistle is a TRAINING tool, not a quick fix. Every dog needs to actually be trained to respond to stimulus (in this case, the whistle) in order to expect results.If you want your (or even your neighbor’s) dog to stop barking, you need to take the time to condition and train the animal! Granted, there are a *few* dogs that will respond immediately to the whistle, you just cannot expect that since it’s not the usual reaction.Please keep in mind that the Acme Silent Dog Whistle #535 was originally designed for sport or working dogs. It is most commonly employed with field training dogs because this particular whistle is fantastic for long distances, it is much less irritating to the average human ear, and it is easily heard by the animal.In dogs, it is primarily used to give commands. In trained cetaceans (whales and dolphins) it is used as a bridge, which is a signal to the animal that it has completed the requested behavior correctly and will soon be rewarded accordingly.All that being said, the Acme Silent Dog Whistle #535 is an incredible training tool that is extremely reliable and useful, providing you know how to use it! As mentioned previously, it is excellent for long distance use and it is not loud or annoying to onlookers/neighbors, while still remaining dependably audible to the dog. It’s stainless steel design is very durable and will last you a long time, as long as you don’t misplace it (believe me, that happens a lot when trainers use a whistle for regular training and exercise sessions).This is, in my opinion, truly the very best training whistle that money can buy. I highly recommend the Acme 535 to anyone and everyone who utilizes whistles in their animal training!