Have you ever tried to make a large flavorful cup of coffee with your single-serve brewer? You can't because single-serve capsules only contain enough coffee to brew a normal 6-8 oz. Cup. That is why the eco-fill max by perfect pod was invented. The eco-fill max by perfect pod holds almost twice as much coffee as a single-serve capsule allowing you to make, big, bold, full-flavored, tumbler-sized beverages in your single-serve Keurig coffee brewer. Just replace the standard k-cup holder with the eco-fill max with by perfect pod holder. You can still use standard k-cups and you can also use the extra-large capacity, eco-fill max by perfect pod refillable capsules.