This was just what I needed for organizing workbooks for homeschooling. No plastic here; metal through and through. Incredibly sturdy, but weighs a ton, so don't plan to use it on a flimsy table.  It is exactly the same dimensions and construction as the 5-compartment MMF Industries Steel Vertical Organizer (I bought the 5-compartment one first, and liked it so much I tried the six, to accommodate a couple extra things); the only difference is that on the 6-compartment one, each compartment is only about 1 3/4 in wide, while on the 5-compartment one the compartments are about 2 1/4 in wide.  My only (small) concern is I wonder if the end walls will eventually be leaning out, because they do flex a little under the weight of the books if the books are leaning toward the outside. Overall, extremely happy with it and would buy another one in a second (but I only have 2 kids).