What is the ruling on purchasing an electrical appliance in installments from a merchant who owns the commodity, with the condition that the commodity will not be received until six months after the installment payments are made and promissory notes are signed to guarantee the merchant's right?

Installment sales are permissible if the total price, including the interest, is clearly stated. It is not permissible for the interest to be separated from the price. The contract must also be free of prohibited conditions, such as a penalty clause for late payment. Furthermore, it is not permissible for the seller to retain ownership of the sold item after the sale, but he may mortgage the sold item to guarantee his right to the deferred installments.