6. Held to maturity debt investments

In March 2024, the Company made an investment of RMB 5.0 million (approximately $688,000) in a 5% promissory note due June 25, 2024 issued by Qingdao Xiaohuangbei Technology Co., Ltd., an unrelated party based in PRC. The maturity date of the note has been extended on two occasions at the request of the maker to December 31, 2025. In February 2026, the outstanding balance of RMB 3,655,525 (approximately $522,000) was paid.