You have a MacPro Nehalem (2009) and you recovered an SSD 2.5 inch: Here are the materials you need! It's a treat to be installed: the instructions are very clear and mounting on a 4 SLOTS internal mac is extremely simple. This will allow the end to really connect easily DD 2.5 inch on one of the 4 internal SLOTS that are 3.5 inches .... A buy eyes closed :-)