Leaks badly.
It does let you shake and mix up the protein well. But no matter how tightly you screw the cap on liquid gets all around the edge and in the threads. Then as soon as you put it down it all runs down the sides and leaks everywhere. It's a horribly cheap and leaky design. I would look elsewhere or just be prepared with a lot of paper towels every time you use it. (and if you find a good one that doesn't leak please post the info here and let me know). Thanks.
Rating: 2 stars