Field help (BOMALT8) 

Multiple bills of materials (BOMs) can be defined for a single product. Each BOM code can be assigned specific management features. For manufactured or subcontracted products this includes restriction of the BOM to a specific site and to specific areas of functionality (for costing or for capacity planning).

Use this field to assign a BOM alternative code to this parent product code.

 See the Use status field (field LIBUSESTA) for tips on using this field in conjunction with the assembly status of this BOM.