Nethysian BulwarkArmor 16
Source Pathfinder #149: Against the Scarlet Triad
Hit points 40 (Hardness 10, BT 20)
Type Shield
Price 8,000 gp
Weight 1 bulk
This round shield is often fashioned to resemble the religious symbol of its dual-natured namesake. A Nethysian bulwark is a high-grade cold iron shield (Hardness 10, HP 40, BT 20) that defends the wielder and can explode with retributive force when struck.
Activate 
envision
Trigger The shield becomes broken when performing a Shield Block
Effect The shield explodes in a burst of bright light and shadowy tendrils, releasing a 15-foot cone of force that must include the attacker if possible. The cone deals 6d8 force damage to all creatures in the area (DC 34 basic reflex).
Traits
Something of uncommon rarity requires special training or comes from a particular culture or part of the world. Some character choices give access to uncommon options, and the GM can choose to allow access for anyone. Less is known about uncommon creatures than common creatures. They typically can't be summoned. The DC of Recall Knowledge checks related to these creature is increased by 2.
AbjurationEffects and magic items with this trait are associated with the abjuration school of magic, typically involving protection or wards.
EvocationEffects and magic items with this trait are associated with the evocation school of magic, typically involving energy and elemental forces.
MagicalSomething with the magical trait is imbued with magical energies not tied to a specific tradition of magic. A magical item radiates a magic aura infused with its dominant school of magic. Some items or effects are closely tied to a particular tradition of magic. In these cases, the item has the arcane, divine, occult, or primal trait instead of the magical trait. Any of these traits indicate that the item is magical.