User blog comment:Dragonzzilla/ME3 Multiplayer DLC I Ideas/@comment-4967682-20120430025126/@comment-4967682-20120430030533

Sounds interesting- they could go off faster than Frag Grenades, but only damage and pester you rather than killing you outright.

Phantom's barriers actually aren't that tough. One fully leveled Overload is more than enough to destroy it. I imagine Guardian's barriers would be slightly stronger (along with their bubble shields, this is supposed to make them more durable than most other 'elite' units to compensate for lack of hitting power).