The trading unit of Shanghai futures and cathode copper standard contracts is 5 tons per lot, and the delivery unit is 25 tons (5 lots) per warehouse receipt. Delivery must be an integer multiple of each warehouse receipt.

In other words, buying copper in the futures market must be based on 25 tons, which is equivalent to wholesale, and the price is naturally cheaper than retail. With the processing fee, the raw material price of 3mm T2 copper is 80 yuan /kg (including tax), which should be reasonable.