I am making some signs for a bank to put in their lobby. They will be going in frames on top of the poles that hold the ropes. Currently, the signs are on a substrate that looks like wood on one side, and is white on the other. It seems to be some kind of plastic. I need to try to find this substrate so the signs I make match the others already in the lobby. Does anyone have any idea where to find it? I really don't even know what it's called. Any help would be greatly appreciated! I've included a picture of it.