The Aegis is the Elite version of the Tower Shield. There is very little reason to use it: it has lower average defense and much higher strength requirements than the Ward, not to mention a higher penalty to movement speed.
Level Requirement: 59
Strength Requirement: 219
Chance to Block: 54% (Paladin) / 49% (Amazon, Assassin, Barbarian) / 44% (Druid, Necromancer, Sorceress)
Smite Damage: 18 to 28
Quality Level: 79