The Babolat custom damp allows you to customize your level of dampening. It features an improved shape to help prevent it from coming off during play. Babolat Custom Damp is a 2 in 1 vibration dampener. The active "O" dampener is for minimal dampening which you can then upgrade using the clear insert for more comfort. Use the O ring only for a more active feel or for additional dampening use with the insert.