It fit perfectly on my large mug from Anthropology and I really like that it can be used with virtually any teacup you might have. The capacity is 16oz so you should have a large mug on hand or share the second cup with a friend. Although it is made out of BPA free plastic, it did not add any weird tastes or odors to my tea. The one thing that I would change is the lid. It isn't really removable but it would be much easier to clean if it was. It's easy to accidentally release the valve on these so I suggest keeping it on the included coaster until you are ready to release the steeped tea.
Perfect Tea Maker provided by Teavana.