there own voices :O
Any standard whistle used by referees in any other sport will work.
they yelled really loud like. no joke. we still do, but we use whistles to get peoples attention
Dog whistles inflict pain upon the dog with their high frequency noise. The use of dog whistles in dog training is cruel and archaic.
Fox 40
no
No, dolphins use a series of clicks and whistles to communicate
NO
NHL
No but however you will need to wear clothes as referees prefer the use of clothes
Referees in football, basketball and soccer use a whistle for various signals.
He blows the whistle , and stops the game.
Personally I use an airhorn because this guy doesn't listen.