The Mixer Ball moves freely throughout the bottle as you shake it, mixing the thickest of drinks with ease.The Mixer Ball works on the same principle as a wire whisk. Made out of electro-polished surgical stainless steel, it circulates throughout the contents of the shaker as you shake it, blending the thickest ingredients with ease. Lumpy shakes are a thing of the past with the Shaker Cup.The flip cap stays where you need it, so it won?t close on your nose Large drink / pour spout ? Just the right size to drink or pour out of. No plastic mixing mesh means easy to clean and empty.