Acme 477/58.5 Thunderer Official Referee Finger Whistle is hand polished and solid brass. High power, medium pitch 115dBA. Big whistle with deep tone, tapered mouthpiece. Comes with fully adjustable cushioned brass fingergrip. It is large thunderer. This whistle is perfect for any sports referee or coach because it gives a deep, loud sound that will carry across any field or court. With an adjustable finger grip that makes it easy to use for any user. The solid brass construction of this whistle means that it will last for years and can withstand any weather condition.