Engineering bay

The engineering bay is a terran building used to improve the quality of weapons and armor fielded by infantry.

StarCraft
The engineering bay upgrades the quality of weapons and armor used by terran infantry. It can lift off.

Development
In the StarCraft beta there existed a structure called the weapons plant. Though canceled before the release of the game, it bore resemblance to the engineering bay's structure.

StarCraft II
The engineering bay reappears in StarCraft II. It can no longer lift off. In the Wings of Liberty single player campaign, the Auto-Tracking and Building Armor upgrades are not available, while the Neosteel Frame upgrade to Bunkers is an upgrade purchased in the Hyperion's armory.

Wings of Liberty
In StarCraft II: Wings of Liberty, engineering bays can be equipped with ultra capacitators, which make weapon upgrades increase weapon speed by 5% in addition to extra damage, or vanadium plating, which allows armor upgrades to increase health by 5% in addition to extra armor. The upgrades cost 5 protoss research points.