Stock paneling

Does anybody know what the grey stock wall panels are made out of ? Where to get it on bulk ?

It loonks like hollow core HDPE but i am not sure. I need the panels that go above the wheel well panel in my crew. I like that stuff and would like to use it.

it's very similar to Coroplast but really no comparison. I forgot the proper name of it but did find the manufacturer and e-mailed them. No reply. They are in Europe and safe to assume it would be very expensive to purchase.

Expanded PVC like Cel-Tec, is available in varying thicknesses but expensive as well.

FRP is an option too but I don't like the smell.

This may work http://www.pennelcomonline.com/us/Panels-and-Laminates/c-689.aspx

Oem Mercedes cargo components are made by Sortimo. They have limited distribution here stateside, but you could call them for availability.

They make some nice stuff...

https://www.sortimo.com/fileadmin/user_upload/sortimo-international/documents/Sortimo_HD_ENG.pdf

Check out Sowaflex...