「FISTFUL OF SILENCE」- tl;dr it's a stand that sucks up sound from around it to fuel its sound-based powers.
A Stand that uses sound/vibration powers. It's main ability is to steal sound from the area around it through its hands, sucking the sounds away into silence as it charges its power up. Sonic power absorbed in this way can be retained indefinitely up to a cap. Beyond this cap, power will be retained only temporarily. The indefinite-time cap might be enough to fight off an assailant or two, but to do more or be on the safe side, the user must keep the stand charged up day-to-day.
Fistful of Silence can use its stored power offensively in the form of sonic blasts or vibration control. It can supersonically vibrate its fist while delivering a punch to add devastating effect, or it can generate resonance-frequency vibration through its hands to create local earthquakes or level structures, given enough time.
These sonic powers can also be used defensively, specifically to guard against projectiles by vibrating the air at subsonic frequencies to slow or halt airborne objects.
The extent of its power depends on how much sound it has absorbed, as it must drain stored power to perform attacks. Because of this, it can be countered by engaging its user in a quiet environment or by fighting silently after its power is drained to ensure it cannot recharge. Conversely, those who try to attack noisily or in noisy places will find themselves at a disadvantage.
Aside from fighting, the user can also employ Fistful of Silence's sonic powers for all manner of sound-based utility. One could shape surrounding airwaves to soundproof rooms, mute specific persons, amplify a voice, generate music out of thin air, or perform true ventriloquism, to name a few examples. The stand would also be able to lend its user a superb sense of hearing, with the ability to pick out the specific single sound of anything nearby or that the user has line-of-sight to, no matter how much noise surrounds the sound in question.
As a fun side note, the user of this stand would be able to put on epic concerts of any kind with little physical equipment.