Apparently "RTD" stands for "ready to drink" and not in reference to some sporty science term. And yes, this is liquid form and comes with a straw and everything! Very convenient. I lived on this stuff post breast augmentation surgery. It was a godsend since I could just about handle reaching into the refrigerator and poking a straw through a seal as opposed to exerting myself by reaching up to shelves at eye level and above for spices to cook with. Chocolate is my favorite flavor-Vanilla a close second. I'm somewhat intrigued by Strawberries N Creme but also a bit dubious. Good stuff though don't expect it to really fill you up-it just gives you a good dose of nutrients and protein and tastes fantastic.