This massive stone and metal shield is taller than most creatures, appearing to be shorn straight out of a castle's walls. In fact, that is effectively what it is, with wheels to allow creatures to swivel it around and rest their arm from typically carrying it aloft, using horizontal defenses to keep safe. As with the tower shield, it provides the indicated shield bonus to your AC. However, you can instead use it as total cover, though you must give up your attacks to do so. The shield does not, however, provide cover against targeted spells; a spellcaster can cast a spell on you by targeting the shield you are holding. You cannot bash with a mobile wall, nor can you use your shield hand for anything else.