A high crit weapon deals more damage when you score a critical hit with it. On a critical hit, the weapon deals 1[W] extra damage at 1st–10th levels, 2[W] extra damage at 11th–20th levels, and 3[W] extra damage at 21st–30th levels. This extra damage is in addition to any critical damage the weapon supplies if it is a magic weapon, or critical damage from a feat such as Devastating Critical.
As with other damage that is added to critical hits, this extra damage is not maximized as part of the critical hit.[PH:217]