Salam in date palm fruit with the condition of a specific value

Question:
He says: Honorable Shaykh, may Allah grant you success. A man gave the owner of a farm fifty thousand riyals, and said to him: on the condition that you give me goods worth seventy thousand riyals from the date palm production. Is this permissible?

Answer:
The salam debt is permissible. He gives him dirhams, and he pays him when the dates are harvested. He pays him a quantity of dates, such as so much and so much, a known weight, for a known term. There is nothing wrong with that. If the conditions of salam are met, this is valid. However, they do not stipulate that its value is so much and so much. Rather, he says: of the good type, or of the medium type. This is what is stipulated regarding the description only: that it is of the good type or of the medium type. As for saying its value is so much, this is not permissible. Yes.