Not just a dampener A single tac placed about an inch from the rim will remove only the high frequency overtone and leave a deeper focused sound with improved response and increased attack.
A single tac placed on the underside of a cymbal near the dome, will slightly darken and mellow the tone. Placed on the edge, the Tac will heavily dampen the sound.
Remove and discard release paper. Always use a clean, dry Tac on a clean, dry surface. Press the tac firmly onto the surface with fingers.