Customers say this shaker bottle mixes powders completely and effectively, with many praising its secure twist-top lid design that prevents accidental opening. Users appreciate the curved bottom and internal mixing mechanism, which they find works better than traditional metal balls. The bottle is described as durable, leak-proof, and the perfect size for daily use and portability. Many note its high-quality construction and unique design that sets it apart from other shakers. However, some customers mention concerns about the sharp plastic edges, stability issues causing it to tip over easily, and occasional leaking problems.