Is it permissible to sell a defective item?

It is permissible to sell gold for silver, or vice versa (exchange), if it is hand-to-hand without delay. As for selling gold for gold or silver for silver, it is stipulated that there must be equality in measure and immediate exchange, based on the Prophet's (peace be upon him) saying: "Do not sell gold for gold unless it is like for like, and do not prefer one part over another; and do not sell silver for silver unless it is like for like, and do not prefer one part over another; and do not sell something absent for something present." Current currencies are subject to these same rulings.