Well i just wanna know if you use it or not, i do btw, it helps me to "feel" the racquet but some pro players like Federer, Soderling, Ferrer and many others don´t use it, these guys use "Powerpads"
btw Powerpad:
"These “dampeners” are called “power pads.” They are usually made of sections of rawhide, although you can use rolled-up scraps of leather grips or inner tube, depending on how professional you want the installation to look. If you don’t have a leather store nearby, or an old, heavy-duty leather belt that you can cut up, Grand Slam Stringers (www.grandslamstringers.com) sells strips of leather that are just the right thickness, already cut to width.
Power pads are typically used in two locations on the racquet. The first is — as you’ve noticed — inside the throat, on the center mains, where they are said to change the feel of the racquet, ostensibly due to a very small amount of “give” compared to having the string on a hard, solid grommet strip. This is probably where the “power” appellation comes from.
The second location is on the first two holes outside of the throat, where the mains have to go through the frame at a sharp angle. Here, the power pads are most beneficial because they increase the radius around which the string must bend, reducing breakage."