Material Master (LO-MD-MM) 
Purpose
The material master contains information on all the materials that a company procures or produces, stores, and sells. It is the company's central source for retrieving material-specific data. This information is stored in individual material master records.
Integration
The material master is used by all components in the SAP Logistics System. The integration of all material data in a single database object eliminates redundant data storage. In the SAP Logistics System, the data contained in the material master is required, for example, for the following functions:
In Purchasing for ordering
In Inventory Management for goods movement postings and physical inventory
In Invoice Verification for posting invoices
In Sales and Distribution for sales order processing
In Production Planning and Control for material requirements planning, scheduling, and work scheduling
In Customizing for the Material Master , you can configure the material master to suit your specific requirements. You do this in the section Configuring the Material Master .