Referee whistle, yellow card play online

It is a simple referee application that can be used in sports etc.

It can sound a whistle, can be used for sports refereeing, training, when you want to call something, pranks, etc.

You can put out four kinds of cards of yellow card, red card, orange card, green card in full screen.
It may be interesting to use it as a referee in sports games or when playing with friends.

It is designed to be easy to use with a simple screen and functions, so please try it.