The Thumbport is made of non-scratching hard rubber and fits under the right thumb on the flute for improved position and balance.

The thumb port is designed to help relieve the strain and stress of playing the instrument.
Simply clip it onto the flute tube around the F key, ultilizing the only finger that does not operate any key - the right thumb, it provides more freedom and the potential to correct the awkward holding of the flute.

– Available in 5 colours:

Black-Grey,
Grey-Copper,
Dusky Orchid-White,
Light Slate-White,
All Red

What is the difference between the Thumbport and Thumbport II?

The Thumbport II has a lower default angle for the thumb. It's a little thicker and more rigid. It has less contact with the flute. And, its extension arm is a little shorter (when attached to the flute, it may go into the case easier for most). Also the end of the extension has a more rounded edge.

If the default angle on the Thumbport II (when the back top end pushes against the flute rib) is too low, one can use a blade to cut off the end a little. The angle can be modified in this manner. Adding isn't as easy as removing; that is the reason why the new shell is longer.

Some players still prefer the older design. The Thumbport and Thumbport II are available concurrently

Analysis:

Mechanically, there are three factors associated with balancing a flute:

1. The mass (weight) of the flute
2. Horizontal rotation
3. Axial rotation

The gravity centre of a flute is located slightly to the right of the left index finger (see letter G in Illustration 1 below). When the knuckle of the left index finger takes up most of the weight of a flute at number 2, the small remaining weight is often assumed by the right thumb.