Fire Extignuisher bed rail attachment

I have seen many different posts about bed rails and their attachments. I would like to see what people have either fabricated or found that will attach to your bed rails. I am looking for something that can attach to the bed rail with maybe just a large flat metal surface that can be drilled out to mount various tools or extinguishers.

Or maybe instead of in the bed, has anyone found a good place to mount an extinguisher, I have a larger one at about 5 pounds so it does not easily fit into compartments. The last thing I want to do is start drilling holes into the truck to mount it, that is why I am looking for something that can be removed from the bed rails.

Thanks