When handling medical equipment, there are many small parts such as caps in instruments used for surgery and treatment. If part of equipment such as a cap is removed at the medical site and the removed part is rounded and easily rolled, it may roll and be lost when removed. Sites handling medical equipment and components need to minimize time loss, but missing parts can cause significant time loss.

If a medical plastic part such as a cap is removed, to prevent the rolling and loss of the cap, adding a rounded rib around the part gives a stopper function. Even plastic medical parts that are easily rolled can be prevented from rolling and losing due to the stopper. On medical sites, time loss is often unacceptable, and it is necessary to design to be  convenient for workers.