Grav Shield
General Information
A Grav Shield doubles the potency of your offensive Base Defense Measures, allowing each one to fire twice against an attacking UFO.
Contrary to popular opinion, the Grav Shield's abilities do not stack. You can build multiple facilites but only the first will allow your defenses to fire again.
Statistics
Construction Time: 38 days
Construction Cost: $1,200,000
Maintenance Cost: $15,000/month