The Blender Bottle is a shaker bottle with a free-floating surgical stainless steel wire ball inside. A total boon for anyone who mixes formulas, shakes, mixes or other powdered drinks. Not unlike a kitchen whisk, the ball moves freely within your drink, breaking up clumps and further mixing the mix as you shake it for a smooth, totally grit- and clump-free serving. I use protein powder and creatine . Previously I had normal shaker bottles that always, regardless of how much shaking I did, left clumps of mix, especially at the bottom of the shaker. I even once spent about 20 bucks on a shaker bottle with a battery-powered mixing wand built into the lid, but the device really didn’t mix any better than a normal bottle, kept falling apart inside my gym bag, ate batteries, and had to be hand-washed since you couldn’t run the mixing attachment through the dishwasher. I’ve been using the Blender Bottle for about four months now after seeing an ad for it in a fitness magazine. The whisking ball is really ingenious, but this is also the first bottle I have ever owned that I can shake without holding onto the lid at the same time. The spout is that secure. I’ve used the Blender Bottle for cold protein powders and other sports nutrition products. The web site lists other uses including pancake batter, salad dressings, eggs, and gravy.