Patent-Pending Carrying Loop Ergonomic Flip Cap and Spout BlenderBall Whisk Inside Leak-Proof Guarantee Wide Mouth Makes it Easy to Add Ingredients StayOpen Flip Cap Won't Close on Your Nose GripperBars Make it Easy to Hold Embossed Ounce and Milliliter Markings Fits in Most Car Drink Holders BPA and Phthalate Free There's Only One Blenderbottle Everything else is just a shaker cup. The BlenderBottle Classic revolutionized the industry back in 2004 with its leak-proof seal, iconic design, and the BlenderBall wire whisk. Now, years later, it's still the best-selling shaker on the market. Why? Because it works. Smooth Tastes Good Say 'goodbye' to lumpy protein shakes and 'hello' to smooth, great-tasting drinks. Our patented mixing system uses the BlenderBall wire whisk—found only in BlenderBottle brand shaker cups—to mix even the thickest ingredients as you shake. Clip It, Loop It, Hang It Integrated with the StayOpen flip cap, the adjustable carry loop lets you hold more when your hands are full and offers a convenient place to attach keys while at the gym. Leak Proof Guarantee The Classic's screw-on lid and secure flip cap keep your gym bag and car seat dry. With a snug twist of the lid and the assuring “snapâ€