Quota

Quotas are limits on how many of a certain item can be imported at a time. Like...only so many pounds of SAT-scores-over-1400-brained dolphin meat can be imported to U.S. canneries every year. There's a quota maximum of, say, a million pounds.

Quotas exist to protect the environment. Tags, or individual license requirements to, say, kill a moose in Wyoming, are required to protect the wildlife there from being over-harvested. Quotas exist on importing another country's trucks into the U.S. to protect Ford and GM and soon Tesla trucks from having real competition from Korea and Japan and soon China.

See: Protectionist.