These are wooden crates trays that you could get at any craft store. I imagine you could also use the old pallets that seem to be everywhere with a little figuring out of dimensions. Then they are painted a coordinated color  and hung in the bathroom. These are nice to store some of the bottles that are inevitably on your counter or the extras some of us buy when we buy for a certain time or from Costco/Sams Club type places. Simple and cheap (or free).