Acme Thunderer Metal Fingergrip Whistle

Fingergrip version of the most popular sports whistles. 

58 version is the official whistle of Canadian Hockey
Brass / nickel plated

Netball and football tend to use the 60.5 model
Rugby tend to use the 58.5 or 58 model

Uses
Netball and football tend to use the 60.5 model
Rugby tend to use the 58.5 or 58 model

Technical
Refer to the non fingergrip versions for sound information
Physically a little larger for the fingergrip element