As effective as it is unique, the patented BlenderBottle by Sundesa is a great way to mix protein and meal replacement drinks while on the go, but it"s also handy for mixing pancake batter while camping, mixing salad dressings and marinades, or just using as a water bottle. This 28-ounce BlenderBottle is great for 8- to 20-ounce drinks. The BlenderBottle is made of BPA-free plastic, while the lid and flip cap are made of #2 HDPE (high density polyethylene). The key to the BlenderBottle is the BlenderBall wire whisk--simply drop it in with your ingredients, screw on the lid and shake. The surgical-grade stainless-steel BlenderBall moves freely throughout the bottle as you shake it, mixing the thickest ingredients with ease and it"s designed to remain in the cup until you"ve enjoyed your ingredients. Before shaking, screw lid firmly onto cup and press flip cap down until you hear it snap closed. For best mixing action, hold gripper bars and shake from the wrist. Powders mix best when liquid is added first.