Perfected Strike (3.5e Maneuver)

''His eyes focused, finding a weak point just under the breastplate. With one fell swoop he struck, and struck hard!''

When you use this maneuver, you must make an attack roll and a Concentration check. If you hit, and your Concentration check matches or is greater than their AC, your melee attack is a critical hit. If you fail the attack roll, you miss like normal, and if you fail the Concentration check, you still hit, but at -2 to attack (which may make you miss) and your attack is a normal hit.

Special abilities which only activate on a natural 20 do not activate with this ability, but other critical-hit activated properties do.