These seem to be very slightly better than my Heads which don't stay in, so I think they're good.
If you have a Yonex racquet these are worth getting. You can feel a big difference when you hit the ball.
These are a better design than my other ones...and they stay in!
The product works as it is described. Yonex makes a great racquet, the vibration dampener works very well on their racquet .