This Wave Biotech Spring Mechanism Tray for System 20 Wave Bioreactor was removed from a working environment and is guaranteed to be in functional condition. This unit came from a local lab that had surplus equipment. We urge customers to view all photos as they show overall condition, included accessories and useful information. Listing only includes what is shown in photos. Sale of unit comes with a 30-day full money back guarantee return policy. We will be happy to provide additional information as well as photos so please feel free to contact us with any questions.