ACME original 'silent' dog training whistle no. 535. Adjustable frequency. Instruction leaflet included. Made in the UK. Good sound quality. Weather-proof. Solid brass with nickel plated finish

No wonder this whistle has been around for 150+ years. Absolutely perfect training device. Easy to use and adjust. It is not silent, but I'm sure there are octaves that dogs hear through this unit as well as the pitch people can hear. Excellent buy.

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!

i have an OLD Acme dog whistle that i've had since about 1985. It has been wonderful and still works great. I bought this "updated" version on the stated information that the new version is good up to two miles. IT IS NOT AUDIBLE UP TO TWO MILES AS ADVERTISED. I bought one but returned it because the sound was intermittent. I returned it and requested a replacement, thinking the first one may have been flawed. NOT SO. The replacement is also intermittent and dogs do not respond any further than 1/8 of a mile. I tested it with my sons two dogs. We had the dogs at 1/2 mile, clear line of sight. No response. Same thing at 1/4 mile. No response. Finally, at less than 1/8 mile they barely responded. If you need the distance, I cannot recommend this product. My dogs have responded to the old whistle up to 1/2 mile or more. My current dog who is well trained and responsive to the whistle also does not even perk her ears when she is a mile out. For short distances, this updated whistle may be fine. If you are looking for a long distance whistle as I was, this is not it. Acme used to make great whistles, this updated version is a huge disappointment for the price. Good luck.

I went with this whistle because I read a blog that reviewed a bunch of different dog whistles and picked this "silent" whistle as it's favorite. It said that, while not completely silent, most testers described the sound as a burst of air since it's supposed to operate on a frequency not detectible to humans.Either my husband and I are Jack Russel Terriers or that's a complete exaggeration.It sounds like a whistle. To me it's not super loud like a coaching whistle but I can definitely hear it just fine and according to my husband it's so loud that he figures yelling at the neighbor's dogs to stop barking would be less likely to give him a headache than this whistle.Furthermore - the dogs reacted to it for about a day ... tops! After that it became so ineffective that we went back to yelling at them. I'm sure this works great on some dogs and is probably more effective if they're your own dogs and you can actually train them with it in some way but since so many other people are asking about getting neighborhood dogs to stop barking - this isn't your savior.