Fast screen off / lock is a free Android app developed by Rain Soft that allows users to lock their devices with just one touch on the app icon. This app is ideal for those who want to extend the lifespan of their device's physical power button. Fast screen off / lock does not require any background service, unlike other apps, and it does not contain any ads or analytics.

The app is easy to use, and it has a tiny size, making it a great option for those who want a simple and straightforward way to lock their devices. However, it should be noted that after locking the device, users cannot use the fingerprint to unlock it, but they can use the pin code or pattern instead. This issue should be considered before installing the app and rating it. The developers have addressed this issue and will provide a fix in the next version. Users who appreciate the app can also consider donating to the developer to support their work.