Durable BPA-Free Construction: Made from strong synthetic material that is BPA-free and chemical-resistant for regular use. Built-In Storage Cup: Bottom storage compartment provides a convenient place to keep protein powder or supplements until ready to mix. Smooth Mixing Design: Includes a plastic mixing net to help break up lumps and create smoother protein shakes and supplement drinks. Wide Mouth & Leak-Resistant Cap: Wide mouth opening makes filling and cleaning easier, while the tight-fitting cap helps prevent leaks during carrying. Hi-Flow Cap & Color Options: Hi-flow cap provides comfortable drinking, with Black and Blue color options for gym, sports, and post-workout use.