A read its some form of high strength plastic board. Ive looked for some before and the closest Ive come up with is this from lowes. Its made from the same pvc material I used for trim and quarter round in my house, and I have some outside in the eaves of my house to cover the gaps. Seems very durable, I have a dickeys incubater I need to replace the wood on the bottom, I thought about buying a whole sheet and rebuilding the whole incubator and seeing how well it holds temps. Cheers