A khiyar (option) that is given to the buyer upon knowing the specifications of the object of sale after purchase, ab initio, without knowing its specifications. In other words, this option comes into effect in cases that involve purchasing an item whose weight, volume, or measurement is unknown. An example is when a person buys an amount of dates whose weight is equal to that of an unknown measure, or an amount of food oil for a specific price per measure of volume. In any case, the sale is considered valid, with the buyer having the option to consummate or terminate it.

Khiyar kashf al-hal is an Arabic term that translates into revelation option.