When buying or selling weights, the balance or scale must be “subject to authorized purchase,” referred to as “embedded for commercial use,” “embossed,” “accepted weight and size.” Or “Certified Class 3”. Only a few products can be served for business. Accurate tests are performed on equilibrium, and names are added to the scale to make the test successful. They were used in hospitals, medical offices, pharmacies, etc. Medical grade, “Approved III. They must be” graded “for treatment or diagnosis. The economy buys or sells gold and silver” II. Must be a “class certificate.”