Get full flavor extraction and good body every time you brew! The Clever Coffee Dripper differs from a normal filtercone by way of a stopper added to the bottom: water only drains once the filtercone is placed onto a cup. In essence, that means the Clever Coffee Dripper combines the best features of French press and filter drip brewing, eliminating the drawbacks of each. With French press brewing, you have control over steeping time, but heat loss and sediment in the cup can be a problem. Brewing with a paper filter is easy and convenient; the problem is lack of control over steeping time (i.e. the coffee begins to drain immediately). By adding a stopper to the filtercone, the Clever Coffee Dripper combines control over steeping time with a sediment-free cup. We call this a "full immersion brewing" method. Like all filtercone brewing methods, you directly control the temperature of the water, ratio of water and coffee and infusion time. As long as the filtercone is kept clean, you can make consistently good coffee. The dripper will fit on cups and thermoses with tops between 1.5" and 3.75" in diameter. Not dishwasher or microwave safe.