The Inventory Master file contains a record for each inventory item in each inventory or warehouse location. Each Inventory Master record stores the current quantities and costs for the item in the specified inventory location, as well as other information about the item that is specific to the warehouse location. A Catalog record must exist for an item before it can be created in the Inventory Master file. Each Inventory record in the system is uniquely identified by the combination of the Location and the Item Number field. A single inventory item may exist in one or more inventory locations. An item must be set up in at least one inventory location before it can be purchased or sold. Each Inventory Master record contains some information that is normalized or synchronized based on the information in the Catalog record for the item (the item description, type, status, product line, etc.) and some information that is maintained independently in each inventory location (the on hand quantity, reserved quantities, allocated quantity, and on order quantity for the item). The Inventory Master file is used to generate the Inventory Valuation report and it is where the accounting cost for the item is maintained.