(1) If the difference between the highest price and the lowest price of a contract is too great. Then the price generally doesn't make much sense.

(2) Too much space; Price operation under the action of capital leverage; Beyond the range that investors can bear, it is inevitable to explode positions.

(3) It seems that (3) the 3)boll line can better analyze the range of price operation, which should be better than simply observing the highest or lowest price of a contract.