Sims 4 Cas Background is inspired by military career and strange Ville game. So, When you download Cas Background that has a Little bit essence of that game. It replaces the main background with a cas background. And then it will remain as the default background in the game. Also, you can download additional files also it comes with the urban sim 4 cc. At a time it will give you a package in one folder. When you download to make sure have to put in the mods folder.
Sims 4 Cas Background Room