Blender ball. Whisk inside. Congratulations. You own the best! BlenderBottle brand shaker cups have led the industry for over a decade, empowering millions of athletes across the globe. Our mixing system utilizes the BlenderBall wire whisk to deliver smooth, great-tasting drinks - anytime, anywhere. No Ordinary Bottle: BlenderBall whisk mixes as you shake. Leak proof guarantee. Easy-grip design. Ounce and milliliter markings. StayOpen flip cap. Easy to clean. Dishwasher safe. No electricity or batteries required. BPA and phthalate free.