It's particleboard covered with melamine type wood grain overlay. The dividers are cardboard like the one I have now. It's pretty sturdy, much more so than the ones that are all corrugated cardboard. I may go ahead and get it-they have only two in stock now and this is just slightly more than I paid for mine about 13-14 years ago.
I got the TOB sale email, but I can't really decide if I like to work with batiks much yet. Guess it's a challenge for me, though I have worked some into projects I've done over the last couple of years.
ETA: Decided not to spend that $$ on that unit. Will look around for something someone is selling really cheap at a flea market or yard sale or giving away.