Electronic Whistles?

[marl]

Has anyone any experience of 'electronic whistles' and would you say they are reliable and loud enough for indoors use in a sports hall?

 

[Vandle]

Never heard of them but what advantage would they have over a normal one?

 

[Uncle Petey]

Never heard of them but what advantage would they have over a normal one?

In this day and age, probably RGB.