1.National Stock Number (FS)
2.Part Number (MG)
3.Color (CL)
The first two are understandable, but Color? The reason for that is the requirement for EDI transactions, such as the Receiving Reports (X12-856) and Invoice (X12-810) to include a Product Description in their line item data segments.
Special ID Indicator
Without one, translation would fail. Because some line items have neither an NSN or P/N, it was decided that "COLOR: NONE" would be a perfectly acceptable placeholder, one that could not create any confusion (beyond its use in the first place).
The Special Product ID adds a fourth category, which is any one of the qualifiers in the list presented.
The Special Product ID appears on the printed DD250 in addition to NSN and/or P/N, if present. However, in the EDI Receiving Report it becomes the primary identifier, with P/N in the Product Description.
Use as ELIN
A potential use of the Special WAWF ID would be to specify an Exhibit Line Item (ELIN) that would be included in addition to the NSN or Part Number. This is not the same as completing the ELIN (below CLIN) and declaring it to be Use(d) as Item ID. That causes the ELIN to be substituted for the CLIN.
Use of the Special Product ID is an evolving concept (introduced in Release 1.4.0215) that will be refined as more contractors find the need to use it. As with many things defined by WAWF and military standards, it is nearly impossible to get definitive guidance from the Government. But rather, novel uses, like "COLOR: NONE" slide into usage only to eventually become standard practices.