"Not Legal For Trade"..?
Answers:
That means you can't sell commercial goods (that need to be weighed) on that scale. Scales in the commercial settings are inspected and regulated so no one gets screwed out of a sale.
For example if you want to sell vegatables from your garden for 1 dollar a pound, legally you can not use your scale to weigh those vegatables.
Other answers:
it means that you could not use your bathroom scale to weigh, say, vegetables to sell to people....
it means that you could not use your bathroom scale to weigh, say, vegetables to sell to people....
Some businesses (think of a deli, for example) sell product by weight. The scales they use to weigh product are designed to determine weight within a margin of error dictated by state trade laws. State governments "certify" scales used for trade in this way by weighing predetermined objects on the scales and checking them for accuracy. Your bathroom scales are not designed to provide the kind of accuracy required for weighing goods, so they are "Not legal for trade."
It means that your scale is not to be used a measuring (weighing) device in order that you may sell items with.
Another words: If you are a gold, silver, or fruit vender,....ect... and you have to weigh the items out to price them for resale your bathroom scale is not a legal scale to use for that purpose.
You would probably need a certified scale made for that, or it would be better to have one in your business of trade.
hope that answers your question.
You can't brag about your to your friends based upon that scale only.