Dejian Zeng may have built your phone.

Or at least worked on it, anyway.

The second-year masters of public administration student at NYU Wagner spent six weeks last year working in a Chinese factory manufacturing iPhones for Cupertino-based Apple.

Six days a week he screwed approximately 1,800 screws into 1,800 iPhones.

Every day. Over and over again.

Why did he do this?

It wasn’t for the wages, which at approximately 3,100 yuan a month (S$627) are not even enough to buy one of the iPhone 6s phones he helped produce.

Instead Zeng teamed up with New York University and the NGO China Labor Watch to investigate working conditions in a Chinese manufacturing plant.

Zeng was tasked as the investigator, and his target was the Taiwanese electronics giant Pegatron.

In a video interview with Mashable, Zeng explained that getting the job was the easy part.

“I just show up in front of the factories, and I saw a lot of people already carrying their luggage and waiting in line so I just step in line and wait,” he recalled.

“And then, when it’s my turn, they ask for my IDs, ask me to show my hands, and they ask me to recite English alphabet. But that’s basically the interview process, and then I was in.”

His daily routine, which included 12 hours spent inside the Pegatron factory located near Shanghai, was equally straightforward.

“So my station is called ‘Station 26: Fasten Speaker to Housing,'” Zeng said.

“So what I do is that I put one screw over the speaker and fasten it on the back case of iPhone, and that’s the only work that I do. It’s just one screw for about 12 hours in the factory.”

Mashable reached out to Pegatron for comment but the company did not respond.