The Construction Turret (aka. "Nano"-turret) can assist and repair nearby units, and it has more build power than any other T1 unit, excluding the Commander. They automatically default to a Fight order when not directly controlled, causing them to repair, assist, and reclaim anything in range—including enemy units!

Use multiple on a single factory to increase build power.

You can also move Construction Turrets to other locations using a Stork or Abductor.

They uniquely damage only other nearby nanos when killed, but self-destruction will not damage nearby nanos. Packing them too close can lead to chain explosions. Initiating a self-destruct (or transporting) one or two can prevent a domino effect.