We teach emergency recalls using this whistle. It's aesthetically pleasing, practically indestructible, and will hang on your key ring for years and years, thus you have it with you any place you take your dog, and because, with correct training (It's very easy, and I'm happy to post that to the training section if people would like), your dog should have such a well conditioned response (think Pavlov), that it is highly likely that you will not need any other devices, and he/she will respond when you do need to recall the dog quickly. It's small and light enough that you won't feel like you have something obtrusive on your key chain. My clients have all told me that this was one of the best purchases they ever made, and less than $10 mostly everywhere they are sold.