The latest Cool Tools updates gives a muscley thumbs-up to the "Blender Bottle," a $7 cup with a steel mixing ball in the bottom for making protein shakes with one hand. (Don't even.)
he 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 only used the Blender Bottle for cold protein powders and other sports nutrition products, but the web site lists other uses such as pancake batter, salad dressings, eggs, and gravy.
Blender Bottle [Cool Tools]