The wood for this bookcase is heavy and well made, but the three-in-one connectors are too light weight for the four heavy sides. And the holes that they to fit into the wood, were drilled slightly too large. any handling of the case and every one of the three-in-one connector would pop out. Could not hold the four heavy sides together.  Also, either the wooden pegs provided were too short, or their holes were mis-drilled also, and they would go all the way into the wood. Had to go to hardware store and buy my own braces. after spending over $200 for this product, that was inexcusable!!
Never again.