These bottles hold 18 ounces of liquid and are perfectly sized for homemade smoothies, juices or flavored seltzer. (Great for standard ice water, too.) They have an extra wide mouth that’s easy to fill and are leak proof since each cap is lined with a rubber O-ring. That prevents both messes and oxygen from getting in and turning your smoothie prematurely brown. From brightly colored drinks to water infused with fruit, these jars make them look pretty on your countertop, car or in your fridge.