This auction is for one Seagate Barracuda ST3750640A 750gb IDE PATA ATA Hard Drive.  Be sure that you need IDE/PATA as this interface is not interchangeable with SATA.  This drive has been tested and I offer a 14-day warranty.  I have multiple drives for sale so you might not receive the serial number shown.  Free shipping if you buy 4 or more.  Delivery signature required.