Merge modules provide you with a standard method by which you can deliver shared Windows Installer components and setup logic to your applications.
The Deployment Toolkit includes a merge module (.msm file) which you can merge into an application’s Windows installer package (.msi) file to make available all of the Enterprise Server components. It also includes a merge module for the Microsoft Visual C++ Runtime, which is a prerequisite of Enterprise Server.
The names of the supplied merge modules are different for 32-bit and 64-bit Windows systems.
For 32-bit Windows systems they are:
For 64-bit Windows systems they are:
See MSDN for more information on merge modules.