A huge retractable shield originally wielded by the locust Maulers. They use the shield to get in close before they charge their enemy. Of course if you manage to take down a Mauler you can use his shield to your advantage.
When aiming down the iron sights the shield will retract out and almost entirely cover your character making you almost invulnerable from the front end but while doing so your character will croutch down almost slowing your character to a crawl. With a little ingenuity you can also plant the shield into the ground to hide behind for some quick cover when you need it. Keep in mind that when the shield is fully expanded you move incredibly slow, also that enemy forces may kick down the shield if it gets in their way.