Blackr is an Android application developed by Neximo Labs that simulates a locked screen over any app without stopping them from running. This app is primarily designed for turning the screen on easily while developing apps, recording videos, or listening to music. You can run the app from anywhere using notification, floating icon, quick tile, or widgets.

The floating icon supports color tinting, transparency, and size. You can also view the date and time, and battery percentage. The app is highly efficient and has a very small size. The best part is that it doesn't require any internet permission or show any ads. It works by showing a black overlay on top of the screen, turning off all pixels, and effectively turning the screen off.

This app is not a lock screen app but an overlay, and your phone is not sleeping while this is on. So power reduction is mostly from less screen usage, and it is helpful to prevent screen burn-in. The app is designed for AMOLED screens and works great on devices like Google Pixel, Nexus, Samsung Galaxy, Note, and more.