20-ounce shaker cup for blending protein shakes, smoothies, and supplements with a patented mixing system utilizing 316 surgical-grade stainless steel BlenderBall wire whisk. The screw-on lid ensures a leak-proof seal and the flip cap securely snaps shut. It also has a wide mouth for easy addition of mix scoops and liquids, and embossed markings for measuring ounces and milliliters. The loop top allows for easy carrying or attaching keys.