I just got one of these. Many other products on the website give the actual dimensions of the mug, but this one just states that it fits in the Mini.  However, when you get it, you discover that it only fits if you pull out the drip tray (which is what the instructions tell you do to).  I have searched for a wide, flat travel/office mug (with cap) that would fit under my Mini in my office without having to pull out the drip tray.  Alas, now I have to keep searching.  The quality of the mug seems fine and it keeps the coffee hot, but it's not the size (height dimension) I was hoping for.