That merge module could then be added to the installation packages of each product that required that particular component.
This saves the effort of having to individually add the necessary files, registry entries, and other components to every installation.
For example, the author of the configurable merge module may allow attributes to be set on components, enable or disable isolated components, specify a bitmap for a dialog, or specify how a custom action is run.
Configurable merge modules are supported only by Windows Installer 2.0 or higher.
[2] There exist a number of pre-created merge modules which install commonly used Microsoft software packages, such as MDAC, ActiveX controls, MFC, SAPI and DCOM.