CSU Training Whistles-Use by Professionals Referees in Football,Basketball,Hockey,Boxing Etc-Oscillates Pure Sound of Whistle Classic Official is the original pea-less refeee whistle. For referees and coaches at every level who want every call to be heard depend on its reliability. Flawless, consistent and penetrating sound keeps the referee in control of the game. Be heard above the crowds and players. no moving parts to freeze, jam or deteriorate. Sound power of 115 decibels. Includes a break away neck lanyard. Classic is the standard choice referees and coaches at all levels, rescue professionals and general safety worldwide. No moving parts to freeze, jam or deteriorate Flawless, consistent and reliable The harder you blow, the louder the sound Will be heard above ambient noise, loud crowds, the roar of engines, breaking waves and thundering gale-force winds Chambers are designed to self-clear when submerged in water Easy to blow and cannot be overblown.