Odor-Resistant Eastman Tritan - Enjoy today's smoothie without tasting last week's protein shake. Rounded Base - Forgot to add liquid first? No sweat. The rounded base on the Pro28 allows the BlenderBall to mix every last bit of powder. Patented mixing system uses 316 surgical-grade stainless steel blenderball found only in BlenderBottle brand Shaker cups The adjustable carry loop is surprisingly handy, freeing up your hands for keys, your phone, etc. Dishwasher safe, BPA- and phthalate-free, carry loop top, ergonomic flip cap, secure screw-on lid