Why did Hawaii hold a trade agreement with the US which allowed duty-free importation of sugar to mainland and what local kingdom give in return for these benefits?

The Reciprocity Treaty of 1875 allowed for the duty-free importation of sugar from the Kingdom of Hawaii to the United States. In return, Hawaii agreed to give the United States the exclusive use of Pearl Harbor for a naval base and to not enter into any treaties with other nations without the consent of the United States.