Shake, Shake, Shake...Shake Your Protein. With our exclusive ON shaker cups, mixing-up even the largest and thickest protein or meal replacement shake is a snap. Each shaker cup has an Extra-Large 32 fl oz capacity and a 3 1/4" opening at the top that makes adding full-size ice cubes a simple proposition. We've also spec'd a beefy, deep-skirt cap that screws down tight to prevent leaking and a tapered bottom that fits into most automobile cup holders. And, unlike cheap knock-offs, this shaker is solid enough to survive dozens of cleanings...even in the dishwasher (top rack only).