This is a great ingenuitive product. I always use the old cups that had the spring ball inside it, and it never fully mixed the protein powder in the water. Using this shaker bottle, I've never had clumps of protein at the bottom and it's always thoroughly mixed. The bottle is easy to take apart and clean in the dishwasher, but I suggest hand cleaning it with dish soap after every use. The bottle itself is really durable. I don't know how many times I've dropped this on a hard floor and it's never even had a scratch on it. I noticed it to be leak proof and I really feel that it's a great value for the money. Think of it this way, this bottle only costs about $1.50 more than the inefficient Shaker bottles with the metal spring ball. Well worth the price for the for a genius solution to the protein shake problem. Read more