A latent option contract that begins to function as a normal option ("knocks in") only once a certain price level is reached before expiration. Technically, this type of contract is not an option until a certain price is met, so if the price is never reached it is as if the contract never existed. Knock-ins are a type of barrier option that may be either down-and-in option or an up-and-in option.

触碰生效期权是指只有在标的资产的市价触及确定的水准时期权才生效