Mo. Rev. Stat. § 413.175: Scales for commercial use to comply with standards — scale sales, sellers, manufacturers to furnish certain labeling information that device is not legal for commercial use.

No person shall sell or install for commercial use within the state of Missouri any weighing or measuring device that does not meet all of the specifications, tolerances, and technical requirements of a commercial device as established by the most recent edition of National Institute of Standards and Technology Handbook 44. Any device sold, not meeting these requirements, shall be identified by the seller or manufacturer as a not-legal-for-trade device by labeling the device as such or by a statement on an accompanying invoice declaring that the device is not suitable for commercial use.