It is extremely simple, volume setting application.
You can set backlight brightness, various sound volume, and manner mode.
There is also a simple widget.

※ This is a free version with banner. Please see below for a paid version without a banner.
(The difference between paid version and free version is only the presence or absence of advertisement banner)
https://play.google.com/store/apps/details?id=com.kitalab.simplevolume


* The brightness display of the widget is reflected immediately when it is set in this application.
* When using the task killer application, please be sure to exclude this application.
(If you try to launch the free version immediately after KILL, the application will be dropped)
* Please do not install and use free version and paid version at the same time.
※ Please see the details of the application and the privacy policy below.
http://www.ne.jp/asahi/sk/k2000/c_android/simplevolume/