These shelves are not sizable to fit as many other racks are.  The plastic stoppers can only go in the positions you see pictured, equal distance apart.  I didn't know that upon purchasing 6 of them, but luckily it didn't matter for my purposes.  If you don't care about that, you CAN'T BEAT THE PRICE!!! Sturdy and can handle quite a bit of weight.  Perfect for organizing my photography and video equipment in the attic.  1 shelf can fit 1 bankers box just fine.