The shelving unit is cardboard. Actual press 1/2 in cardboard.  Don't know what you put on these but it isn't weight as mine snapped in half immediately with just a little pressure. The frame is paper thin, bends at the slightest pressure and the connectors are space incorrectly on some.  Absolute trash, do no buy these shelves.  Hell don't buy from wayfair.  Its not worth the price reduction if you have to go buy it again anyways.