AutoCAD Mechanical is the foremost software for mechanical design processes. The extremely comprehensive library with components and tools for automating general drawing tasks help make this Autodesk AutoCAD software more effective than ever. 

AutoCAD Mechanical 2015 is the ultimate mechanical engineering design software and is fully interoperable with other CAD systems, making Mechanical 2015 easier to use than ever.

When you purchase a licence for Autodesk AutoCAD Mechanical 2018, you also have the right to use the 2015 version. This is the only way, in the new licensing structure, to "buy" AutoCAD Mechanical 2015 (further information on licensing).