Sturdy and with the middle panel, which helps to keep the pens in place. I literally got one for free, using the bonus points I earned by buying the 320 alcohol markers previously, and I wouldn't get a better deal elsewhere. Although I would prefer individual slots for each pen, I understand that for this material it would be too heavy and expensive to make, also larger for storage. It is OK as it is and my pens are now organised by alphabet and numbers for a super easy allocation and my own swa...