Shaker Cup uses the Blender Ball wire whisk to deliver smooth protein and nutrition shakes with ease. Building off of the tried-and-true design of the Blender Bottle Classic, the Classic Series shakers offer customer-requested features and unrivaled refinements. The rounded base allows the Blender Ball whisk to mix every last bit of powder. Blender Bottle uses premium, durable Eastman Tritan plastic to help keep your bottle fresh and odor-free. Stain and odor resistant. The patented mixing system uses the BlenderBall wire whisk. BPA and Phthalate free. Wash immediately after use. Top-rack dishwasher safe. Why the Whisk Ball? Unlike stationary mesh grates or other in-lid elements, the BlenderBall whips around inside the bottle as you shake. The BlenderBall is springy and bounces off both the top and the bottom of the bottle, working against the liquids. Made from electropolished, 316-grade stainless steel, the same material used in surgical instruments and implants. Add ingredients like peanut butter, applesauce or yogurt to your protein or meal-replacement shakes for added flavor – the BlenderBall whips them in with ease. The BlenderBall will never rust, chip, or peel. Every BlenderBall is manufactured using a unique multistage process designed to ensure safety, quality, and longevity.