I was reading about exotic options and I came across something new. One touch down no touch up option and the other one I saw was One touch up no touch down option. I would like to understand how it works. Does it cease to exist when the barrier is touched or on the expiration date of the option? A regular one-touch option ceases to exist immediately after the specified barrier is touched no matter how much time is left to the expiration, but a no touch option is also part of the options above so I am not sure how this is going to work? An Example for the One touch up no touch down option, If the upper barrier is at 110 and the current price is 100 and a lower barrier is at 90. What happens if the price goes to 90, or 110, or stays between 90 and 110?