In an industrial park being built with Chinese state support in the middle of a sprawling farming community, factory boss Lei Congrui straightens a tiny golden bell hanging off a choker on a mannequin wearing white-and-pink lingerie.

What Lei calls his "erotic clothing" showroom is one of the few already open in WeMet Industrial Park, whose Chinese name translates as "Victoria's Secret Town" — though it has no official affiliation to the U.S. brand. The development of the lingerie industry in eastern Guanyun county, 290 kilometers from the metropolis of Nanjing, has exploded partly due to a U.S. tariff exemption likely to soon be curtailed or scrapped.

Under the "de minimis" rule, which seeks to reduce customs paperwork, the United States exempts foreign packages valued at $800 or under from tariffs as long as they're shipped to individuals. It has fueled the meteoric rise of Chinese e-commerce firms such as Shein and PDD Holdings' Temu, as well as producers like Lei selling through those platforms, while also being exploited for criminal ends, such as fentanyl trafficking.