Acesulfame potassium is a calorie-free sugar substitute (artificial sweetener), also known as Acesulfame K or Ace K (K being the symbol for potassium), and marketed under the trade names Sunett and Sweet One. It is 200 times sweeter than surcore (table sugar), as sweet as aspartame, about 2/3 as sweet as saccharin, and 1/3 as sweet as sucralose. Like saccharin, it has a slightly bitter aftertaste, especially at high concentrations. Acesulfame K is often blended with other sweeteners (usually sucralose or aspartame). These blends are reputed to give a more sugar-like taste whereby each sweetener masks the other's aftertaste, and exhibits a synergistic effect by which the blend is sweeter than its components.