This dampener will forever be linked to one of GOATs, Pete Sampras. As a fan, this is a must have. As one who plays tennis, this works great at absorbing vibration and eliminating the natural pinging sound when a racket hits a ball.
However, as a one-size-fits-all item, it is sometimes prone to popping out when it is hit directly or if your racquet has a open string pattern, a 16X19 for example.
Overall, a great, simple, bang for your buck item. I would recommend getting a brightly colored red dampener, because the black one is slightly harder to find once it pops out.