These additional armor plates offer protection against explosions and shrapnel, granting you a +2 enhancement bonus to Reflex saves against weapons with the explode special property. As a full action, you can place a grenade inside a reinforced, eggshaped compartment in the armor upgrade. As a standard action, you can detonate the grenade. This explosion is centered on you, but the upgrade creates a temporary containment field that shields you from the explosion. In all other ways, the grenade functions normally.