reference  number  listed  more  than  once,  with  each listing  having  a  different  NIIN.  For  proper identification, you must then select the NIIN from the line entry showing the FSCM for the company that made the needed part. The  identification  lists  of  the  Federal  Supply Catalog include the FSCM in the item descriptions. The introduction to each section includes a numerical listing of all FSCMs included in that section. IDENTIFICATION TO A CURRENT NSN To obtain required material, you must first find its current NSN. There are three basic methods of entry you may  use  with  the  catalogs  to  obtain  this  information: 1. 2. 3. Entry In Entry with an NSN (which may or may not be current) Entry with a reference number (manufacturer’s part number, Navy drawing number, or other reference  number) Entry  with  a  noun  name  and  or  physical characteristics   description With NSN actual practice, if you already have the NSN, you just submit the completed requisition to the supply department. Entry With Parrt, Drawing, or Piece Number A reference number is generally any number, other than a current NSN, that can be used to identify an item or to aid in determining the current NSN. Reference numbers, therefore, include old FSNs, electron tube numbers,  and  electronic  equipment  circuit  symbol numbers.  There  are,  however,  two  additional  important types of reference numbers that you can convert to national stock numbers by using the C-MCRL. They are (1) manufacturer’s part numbers and (2) Navy drawing and  piece  numbers. Manufacturer’s part numbers are numbers assigned to parts by the manufacturer who designs and builds the equipment. The manufacturers assign the numbers for their  own  use  in  cataloging  and  identifying  their  own material. Some manufacturers use part number systems in which their plan or drawing and piece numbers form all or a portion of their part numbers. Navy drawing and piece numbers were assigned originally  by  Navy  technical  commands  to  identify items in equipment built and or designed by those commands. Some items may have both manufacturer’s part numbers and Navy drawing and piece numbers listed  in  various  reference  publications. When you first try to determine an item’s current NSN, you will probably look for a manufacturer’s part number or a Navy drawing and piece number. There are several possible places to look for such numbers: 1. 2. 3. 4. 5. On an Allowance Parts List (APL). On the part to be replaced. The part number may be stamped on it. In equipment technical manuals. hey may refer to  a  manufacturer’s  part  number  or  Navy drawing  and  piece  numbers. On equipment plans. Plans available on the ship may contain Navy drawing and piece numbers. In  EIMB  reference  data. Technical  manuals,  furnished  by  the  manufacturer, contain  a  detailed  description  of  equipment  and instructions  for  its  effective  use.  Normally,  the  supply officer  does  not  have  technical  manuals;  they  are maintained  and  used  by  the  ship’s  technicians  in maintaining the complex equipment installed in the ship. They can serve as a basic source of identification information for repair parts. To obtain a current NSN when you know a reference number, enter the C-MCRL to determine the NIIN. When the NIIN is listed, check to ensure that the FSCM coincides with that of the manufacturer of the part. When the number is listed more than once, you will need  to  obtain  the  manufacturer’s  code.  When  you obtain the correct NIIN, update your records to reflect the current stock number. Entry with Noun Name and or Physical Description The  third  method  of  obtaining  a  current  NSN involves  beginning  the  search  with  a  physical characteristic or noun name description of the item. There  are  two  different  methods  of  describing  an item other than by the NSN. The first method uses a physical   description   of   the   item   and   perhaps   a description   of   its   electrical,   chemical,   and   other properties.  (This  type  of  description  is  similar  to  that provided  in  mail  order  catalogs.)  The  second  method, which we covered previously, uses only a reference number; that is, manufacturer’s part number. Most of the 3-20