This attachment is a must buy!  It automatically makes the perfect froth for any espresso drink (or even hot cocoa).  The milk reservoir detaches, so you can store any unused milk in the fridge... or you can place the tube directly into a carton of milk, which I find is best since it makes clean up extremely easy. Best of all, it is compact and doesn't take up a lot of counter space.  It only adds a few inches to the espresso maker, and its well worth it!