The tuning fork activator is a handy tool for working unweighted tuning forks. Just place it in your pocket or on a flat surface and gently tap the fork on the edge of the activator.
YES! It's a hockey puck with an Om imprint but it works great! Practitioners -- put it in your pocket and tap your forks against it for a muffled but strong vibration.
The activator is made of vulcanized rubber.