1. Comprehensive copper is quoted by electronic disk. Electronic disk is a 24-hour transaction of computer matching quotation. Comprehensive aluminum and comprehensive copper.

2. London Copper is an open bid of floor traders, and the transactions are paired. London zinc and London copper.

3. London copper is quoted in the London spot market. London is aluminum now and London is copper.

4. Copper premium is the difference between spot market and futures market. The spot price is higher than the futures price for premium, while the spot price is lower than the futures price for premium, and the spot price is equal to the futures price for liquidation.