What is an Istisna' contract? What is its ruling? And what are its conditions?

Firstly: A manufacturing contract (Istisna'a) is binding on both parties if its pillars and conditions are met.

Secondly: It is a condition for a manufacturing contract that the type, kind, quantity, and desired specifications of the manufactured item be clearly stated, and the delivery date be specified.

Thirdly: In a manufacturing contract, it is permissible to defer the entire price or to pay it in known installments and at specified times.

Fourthly: A manufacturing contract may include a penalty clause by agreement of the contracting parties, unless there are compelling circumstances.