I live in China and I often buy this film. This is an aerial reconnaissance film that was made by the Lucky(乐凯) company for the military many years ago, but it became idle in military storage due to technological upgrades. After the confidentiality period, it was released into the market as large plates/sheets, and some enthusiasts and packagers re-packaged it into 135/120 formats. Its performance is quite good, but the condition varies from batch to batch due to different storage environments. In China, these films are called "aviation rolls,(航空卷)" and they usually cost 15-22 CNY (2-3 USD) per roll. If you're interested, you can check it out on Chinese websites.