Foam insert for rear under floor storage

Does anyone sell foam to fill in the storage compartments under the floor in the rear? I'm looking to install pick-foam to fill the space up, customizing it around items I like to keep in there to prevent them from rolling around, rattling, etc.

I want to fill the compartments with foam like in the case on the attached image.

If this has been covered before, I apologize. I gladly accept any insight.