Direct mail parcels are generally for personal use. If you declare them as personal items and then resell them, it constitutes smuggling. When mailing large quantities of similar, non-consumable items exceeding a certain quantity (e.g., 500 iron kettles, 300 CD players, 200 shakuhachi, etc.), customs will consider it beyond reasonable personal use and initiate an anti-smuggling investigation. If you are indeed purchasing them for commercial purposes, please declare them as imported goods.