Bought two of the 448 ball bearing models-rev-a-shelf’s top of the line cabinet organizers. One of them was seriously damaged but Wayfair replaced it promptly with no issues and the new one was damaged also. Rev-a-shelf does an absolutely terrible job of packing their products. The instructions say it is a 30 minute job to install these-that is laughable. It will take you close to an hour to adjust the  shelves properly so plan for much longer to install. Once installed they are very slick and work very well it’s just that it is an ordeal to get there.