I purchased your fiftyfifty shaker bottle on Saturday because I love my protein shakes to be cold, and stay cold! The bottle does just that, keeps my protein cold until I finish it. However, the shaker lid will not flip all the way back which means when you take a drink of your shake you get a lid to the forehead. Also, the gasket to keep the lid sealed requires quiet the attention to make sure it is in securely. Overall I think this is a good product.
Love these bottles and accessories, great product for a great price!