What is this thing and how do i get it? http://imgur.com/uH7axnZ

Is it like a trap of some sort?

It's part of the main quest line if you go with a certain faction over another. Can't say much more than that without spoiling everything.

ye following certain quest line you get some special items you can build. you need to build that thing to advance in the main story. and from the minuteman i got a cool artilery

oh so you get it through a quest? but you can build it on your settlement, not just in your quest right?

(spoiler->) ....is it when you have to activate Prime for the BoS?

no, it is part of the main quest no matter what faction you choose to complete.

which faction is it? I played the game for the MM so idk about spoilers. Also, like i asked already, can you build it on any settlement after you get it?

oh okay then. I think i havent gotten up to that part for the MM quest yet. so you can build that thing on any settlment? what is it called?

What is that thingy called?