[Substratum] Pixel Black for OOS is a free personalization app developed by DeadmanxXD for Android devices. This black substratum theme is designed to provide a Pixel ROM look to the system apps and invert the colors of third-party gapps from dark to black. The theme is compatible with all other devices and ROMs using substratum with root.

The app comes with several features that include enabled always-on display, stock Pixel icons for QS tiles and status bar, adaptive icons support, Pixel theme accents, and black backgrounds for dark mode gapps. The app also has a Pixel-like settings dashboard and many other features.

To install the app, users need to download and install the theme, open substratum, give it full root permissions, and allow system modifications. After selecting the theme, users need to choose the combinations they want to apply and click the floating action button to build and enable the theme. Once the installation finishes with no errors, wait until SystemUI restarts. Root is a must for this app.

Overall, [Substratum] Pixel Black for OOS is a great app for users who want to customize their Android devices with a black Pixel-like theme.