I purchased four of the 18"x36" 4 shelf units through Spreetail (Amazon) and they have several defects such as needing to remove excess plastic from the tubes to get them to fit however, I still like these shelves over others available. My last shipment of two units was damaged but seller immediately sent replacements. Other than needing better packaging for shipping, I highly recommend this brand and seller.Update: The replacement shelves were also damaged which I requested another replacement. Spreetail is now refusing to send out replacements until they receive the returns even though they didn't wait for return with the first replacements. I believe this practice is not consistent with Amazon policy. I should have 30 days to ship the return. At this point I cannot recommend this seller. I am considering returning the first two undamaged shelves also and buy from someone else. This is without a doubt the worst customer experience I've ever had from an Amazon seller.