Powerpads are pieces of leather placed between the string loop and grommet on a tennis racket.

They were originally used in wooden rackets to soften the angle the string goes into the rackets grommet hole. This was quite useful for the natural gut used at the time.

Later, powerpads were used as a sort of precursor to shock absorbers. Players claimed the leather pieces dampened the feel from the racket.

But the name "powerpad" suggests it adds power to the racket. There is actually a case for this: In the above photograph, the pieces of leather lengthen the six central main strings slightly, which can allow for slightly more string movement, leading to a slightly springier setup.

Of course, it is likely this improvement is almost negligible, especially in modern rackets which are already very powerful to start with. It is likely any difference in feel felt by use of powerpads is felt due to the 1 gram or so of mass added by the powerpads.

Powerpads are quite old-fashioned, so very few players will use them on a regular basis today. One of the only professional tennis players who still use powerpads is Roger Federer (pictured above).