An alloy used in the production of silicon, transformers and electric motors made up more than half of North Korea’s exports to China in November, customs data shows, though an expert warned that low overall trade volume makes it difficult to draw firm conclusions about the data.

According to China’s General Administration of Customs (GAC), Pyongyang exported $3.7 million worth of ferro-silicon to China last month, making it the country’s top export. Electricity and silicon carbides (a naturally occurring mineral with semiconductive properties) followed closely behind, making up 25.2% ($1.6 million) and 12.4% ($814,000) of the North’s exports