Melamine shelving is a heavy pressed wood/glue product - almost like fiberboard - which has a very thin melamine layer (think plastic) glued onto it. It's often used for shelving and furniture. The upside for reptile enclosures is that it's easy to clean, will hold heat and humidity very well, is fairly inexpensive, good for DIY projects, and is durable if you keep larger snakes. The downside is that it weighs a lot.