Is it permissible to sell by installment, with 25% taken as a down payment, and the remainder paid in monthly installments, if the seller purchases the goods based on specifications determined by the buyer?

For the transaction of selling a commodity to be permissible, the woman must buy the commodity, and it must enter into her possession and warranty. Then, she sells it to the one who ordered its purchase. There is no harm in selling it for more than she bought it for, and the buyer must not conclude a contract with her until after she possesses and takes hold of it. What happens before that is a promise to sell. However, if the commodity is described in terms of liability (dhimmah), it is not permissible to sell it in installments because it falls under the category of a Salam sale, which requires the delivery of the capital at the contracting session.