Tennis Score Manager

I'm a amatue tennis player. Whenever I played a tennis, I needed this kind of tool.
I found several apps but those are not free and need a registration.
So, I made this app by myself.
Main features:
* Enter your game result; win or lose
* Keep your score
* Undo your score
* Keep the service order
* Play scoring sounds
Remarks:
* Play type to support: Both Double and Single
Feel free to use it and welcome to your feedback.