Tic Tac is a brand of mint produced by the Italian confectioner Ferrero. They were first introduced in 1969 and come in a variety of flavors from fruity to minty. For a long time, the individual Tic Tacs were colored to correlate the flavor they were, but today in many countries the Tic Tac box is colored to represent the flavor and the actual Tic Tacs are just white.
The Ti Tac container itself has become very popular and recycled by many for other uses with its flip open tab. Each Tic Tac weighs just under 0.5 grams. Since the US regulations states that if a single serving contains less than 0.5 grams of sugar it is allowable to express the amount of sugar in a serving as zero.
A single serving of Tic Tacs is a single Tic Tac, so in the US they are labeled as having zero sugar, even though it is their main ingredient.