This type of structure provides ways to defend or repair your base or fleet.

Note : the stats as they are listed in the table below are taken from HD Xyth. In older versions of the game, some cards might have different stats.

Card	Race	2nd Race	Rarity	Energy cost
Antigrav Shield	RV		common	2
Antimatter Field	CA		common	2
Armored Growth	MT		elite	3
Dark Energy Field	CA		common	2
Dimensional Link	RD		elite	3
Growth Spire	MT		common	3
Nanobot Tower	RV		common	2
Nebula Spire	XY		elite	2
Restoration Field	HU		common	3
Shield Generator	HU		common	2
Shield Spire	CC		elite	3
Support Spire	CC		common	2
Virus Barrier	TM		elite	2