Franklin's most famous invention is the lightning rod, which he developed in the mid-1750s. He also invented a number of other devices, including the Franklin stove, a more efficient type of fireplace, and bifocal eyeglasses. Franklin also made improvements to the printing press and other mechanical devices.
However, Franklin's primary contributions were in the areas of science, politics, and literature. He was a leading figure in the American Enlightenment and a major contributor to the American Revolution. He also served as a diplomat, a printer, and a publisher.
In summary, Benjamin Franklin was not primarily known for inventing, although he did make a number of important inventions and improvements to existing technologies.