Attacks made while stealthed and for 6 seconds after breaking stealth cause an additional 10% damage.
Master of Subtlety is a passive rogue ability learned at level 10 for those with the Subtlety specialization. It increases damage while in [stealth] and for six seconds after.
Patch changes
Patch 3.2.0 (04-Aug-2009): Being under the effects of [Cyclone] when the buff from this talent is about to expire will no longer make it last indefinitely.
Patch 3.1.0 (14-Apr-2009): The amount of time remaining on the damage bonus for this talent is now displayed.