By Don Reisinger

One NYU graduate student got an up close and personal look at what it's like to produce iPhones for a summer project last year. And now he's telling his story.

Dejian Zeng spent his summer last year working at ChangShuo factory in China. The factory, which is owned and operated by Apple (AAPL, +0.12%) manufacturing partner Pegatron(和碩), is home to iPhone production and at the time, Zeng and his colleagues at the facility were busy readying Apple's handsets for store shelves. Zeng detailed his experience working at the facility in a lengthy interview published by Business Insider this week. He also shared how much he was paid, where he lived, and what it's really like to attach a screw to an iPhone case.

Here's a look at some of the major things Zeng revealed about his time working at the Pegatron facility:

  • Zeng started working on the iPhone assembly line screwing a speaker to the handset's case. He would input the single screw into handsets all day without being allowed to use electronics to help pass the time.
  • Zeng was told by his manager from time to time to keep his “voice low” when he would strike up a conversation with other workers.
  • He said that he lived in a dorm with seven other people and was shuttled to the facility by a Pegatron bus. Sometimes, the dorm doesn't have water available for residents to shower, he said. However, residents can watch videos for free over the dorm Wi-Fi.
  • Zeng worked the night shift and would start working at 7:30 p.m. local time each night. After two hours, he was given a ten-minute break. Zeng could take a 50-minute lunch break two hours later.
  • Many workers are tired, Zeng said, and try to sleep. However, if they're caught laying down, their IDs will be swiped and managers will yell at them, he said. In some cases, workers are fined.
  • Employees generally work eight hours each day but are sometimes required to work overtime, which can add an additional two hours to two-and-a-half hours to the day. Including breaks and lunch, workers spend 12 hours in the facility, Zeng said.
  • Zeng said that most workers do the jobs for the money to support their families. However, he doesn't believe anyone sees a job in the facility as a career.
  • He was paid 3,100 yuan (about $450) and housing for a month's work, including overtime. But overtime is, in most cases, mandatory, Zeng said.
  • Security at the facility increased significantly when production shifted from the iPhone 6s to the iPhone 7. The company turned up metal detector sensitivity so high that the sensor would sometimes detect metal in female workers' bras. Those workers then had to change their clothes to get into the facility, Zeng said.
  • During iPhone 7 production, Apple had staff in the factory each day supervising assembly.
  • Pegatron does a good job of banning underage workers and has impressive safety training, Zeng said.

Apple did not immediately respond to a Fortune request for comment on the Business Insider interview.

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TNL Editor: Olivia Yang