Get a boost with Cliff Shot Blocks. Made for endurance sports, Shot Blocks are chewable cubes containing 33 calories. Each serving of three pieces has at least magnesium, 70mg sodium and 20mg potassium to keep muscles functioning properly. Available in a large variety of flavors, including some with caffeine and one option with three times more sodium. No high-fructose corn syrup is added and they come in an easy-to-open package.