This brush creates you a texture effect, based of some dusty dias which I scanned in high-res. You can texture your background or give your handletterings some very cool effects in the procreate app. 

With this download you get a .zip file. In the decompressed folder there are 6 brushes for procreate and a short description for installation.

 

Have a look at this brush: https://www.fischer-on.de/index.php/shop/procreate-brushes/6-dusty-dia-texture-brushes-procreate-detail