This talent executes a weapon-shield-shield attack chain in rapid succession.
Each attack gains +10 attack.
Each shield attack gains +2 armor penetration.
If the target fails a physical resistance check vs the attacker's strength attribute, it is stunned for 4 seconds.
Stun duration is modified by party size. The exact formula is very similar to the Mind Blast, with base 4 seconds duration instead of 3: (4.0 + (4.0 - (Party Size))) * (Target Rank Duration Modifier). Sources: talent_constants_h.nss, talent_singletarget.nss.
Shield Mastery adds the strength bonus a second time for the shield hits. The bonus is not increased if the hit is critical.
Conjuration time: 1s.
20 additional Threat is supposed to be drawn from the target. As of Patch 1.02, only damage-based Threat is drawn.
Even if the attacks miss, the stun will still occur if the target fails the resistance check.