First: buying style

In this case, investors expect that the underlying price will fluctuate greatly in the near future, but they don't know which direction it will fluctuate, so they adopt the structural reform strategy to arbitrage. The structure is as follows.

Second: sales type

In this case, investors' expectations are just the opposite, thinking that the price fluctuation of the subject matter is small in the near future.

Option strategy: sell call option (b) at a higher strike price and sell put option (a) at a lower strike price.

Just turn the image upside down.