In an attempt to bring mildly acidic reverse osmosis filtered water back to the slightly alkaline level which most people are used to for water, there are modules available for water filter systems to add minerals back to the water. These brackets were designed to attach a number of these modules in place on a wall. In the picture, this model is the blue bracket. The white brackets came with the mineralizing modules. These brackets are sized for the particular iSpring mineralizing modules in this filter system. If you need a different size, you can either rescale the STL file (which will also rescale the screw holes) or modify the included FreeCAD file. The model itself is not particularly well-designed for filter modules of different sizes and was really only designed as a very quick way to mount these particular modules. I'm mostly just posting this in the hopes that it will work as a good starting point for your own project.