From Solo-Fill – the refillable K-Cup for the Keurig coffee machine.
This device works with any Keurig coffee machine as a K-Cup replacement filter. Just add your favorite coffee to the Solo-Fill and place in the Keurig to make a perfect cup of coffee. With this you can use any brand of coffee, especially brands that do not (yet) have a K-Cup version of their coffee. You can even use your own home-roasted ground coffee!
Some say the plastic ones have a 'plastic' taste. If you plan on using these often, we would go with the stainless steel ones. Even if the plastic ones do not taste or smell like plastic, we would think they would wear out and need to be replaced often.