Official Whistle Of Hockey Canada Waterproof pea Easy Blow - Instant Response Crisp Sound The ACME Thunderer cushion grip whistle is the best whistle in officiating. Same great hockey referee whistle design with a sleek matte black design. Large, tapered mouth with fingergrips. This is the official whistle of Hockey Canada. Also includes black fingergrip cushions and black gator grip mouth guard. (Acme number 477/58.5)