When a North Korean defector and the Human Rights Foundation planned to distribute Sony Pictures' The Interview to North Korea via balloon air-drops of DVDs and USB sticks late last year, they knew there was a good chance that the movie would be seen by at least some of the secretive country's citizens. That's because the North Korean government hasn't been able to stop the spread of low-cost digital media players smuggled in from China—many of them manufactured almost exclusively for the North Korean black market.

Reuters reports that an inexpensive portable DVD and digital video player, dubbed the "notel" by North Koreans (a portmanteau of notebook and television), is available widely on the North Korean black market for about 300 Chinese yuan—roughly $50. The devices have a small built-in LCD display, can be easily concealed, and can be recharged from a car battery.

A North Korean defector told Reuters that he had smuggled 18,000 notels into North Korea in 2014, and that the factory that made them was probably only still in business because of North Korean demand, since the devices have gone out of style in China.

The spread of the notel has been so difficult to keep in check that the government of the Democratic People's Republic of Korea has legalized the device. However, the government requires citizens to purchase official notels through state-owned stores and register their ownership. The internal radio and television tuners of sanctioned notels are locked onto official government broadcasts.

In the meantime, North Koreans have become more public about their use of the notel and about their viewing habits—including South Korean and Chinese soap operas. There's been no word, however, on how The Interview has fared in the North Korean video black market.