What is diffrence between Istisna and Ijarah?

Under Istisna,  the manufacturer either uses his own material or he arrange for the material himself whereas under Ijara the material  is provided by the customer and the manufacturer uses only his labour and skill meaning that his services will be hired for specific fee paid to him. Further, under Istisna the purchaser has the right to reject the goods after inspection if  these are not according to the specifications agreed at the time of contract whereas under Ijara this right of ispection does not exist.