Abjuration [Force]
Level: Sorcerer 1, Wizard 1
Components: V, S
Casting Time: 1 standard action
Range: Personal
Target: You
Duration: 1 minute/level (D)
Shield creates an invisible, tower shield-sized mobile disk of force that hovers in front of you. It negates magic missile attacks directed at you. The disk also provides a +4 shield bonus to AC. This bonus applies against incorporeal touch attacks, since it is a force effect. The shield has no armour check penalty or arcane spell failure chance. Unlike a normal tower shield, you can’t use the shield spell for cover.
Source: Player’s Handbook (Page 278)