Okay i hold my hands up, i saw these whistles and immediately thought 'bargain!' there a must have. I'll tell you right now, they are not. The sound which comes out of these whistles is not one of a good, decent, whistle.. it is one of which sounds like a cat being strangled by a rope. They look cheap and tacky and the sound of them resembles this.
If you want to buy whistle, do not get these.. go for a single whistle for the same price, but with triple the quality.