Color Changing Cups Mason Jar for Kids Bundle of 4 Items Color Changing Cups Mason Jar for Kids Bundle of 4 Items These cups are are dishwasher safe and FDA compliant. The cups and straws change color when you put a cold beverage in the cup. These cups are plastic and are great for smaller children. If they get banged up, no worries. These cups are reusable. Each mason jar comes with a twist off cap, color changing straw and comes in 4 colors, yellow, green, pick and blue. Satisfaction is Guaranteed. Order yours today while supplies last.