I will go into details of the specific fan model number / IBM part number in the near future. I am in the process of discovering all the model numbers associated with this fan design (it looks like there are several iterations) and I am working to secure as many sources for these fans as possible. I want to keep costs as low as possible, and secure the appropriate amount of fans to satisfy the estimated demand so this can remain as affordable as possible. As explained earlier, it is easier for the customer to purchase everything from one vendor (salvagedcircuitry) than have to shop around and source components from a wide range of vendors, so I am in the process of acquiring these fans en masse.