there own voices :O
Any standard whistle used by referees in any other sport will work.
Referees and officials commonly use equipment such as whistles, flags, cards (yellow and red), a watch or stopwatch for timekeeping, and a notebook to keep track of game events and infractions. Additionally, they may also use communication devices like headsets to stay connected with other officials during the game.
Yes, the NHL typically assigns different referees for playoff series compared to the regular season. The league aims to ensure that the officiating is consistent and of high quality during the playoffs, often selecting its most experienced referees for these crucial games. The selection process is based on the officials' performance throughout the season and their ability to handle the heightened intensity of playoff hockey.
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
Before using a whistle, officials used hand signals or flags to communicate calls during sports games or other events. Whistles eventually became popular for their loud and clear sound that could easily grab players' attention and signal them to stop or start play.
The NHL mandated the use of helmets for players starting in the 1979-1980 season.
NHL
Referees in football, basketball and soccer use a whistle for various signals.