Mix up your pre-workout or protein shake in the 28 oz Contigo RbW Shaker Bottle. Convenient measurements marked on the side in both millileters and ounces make it super easy to mix the right amount of liquid with your powder. The unique weighted shaker ball and rounded bottom are engineered to give you the most efficient shake, so you get a perfectly blended drink instead of clumps and build-up. The leak-proof lid and carry handle mean you can shake, grab, and go without worrying about the drink spilling all over your racquet bag.