Give each sellable version its own stock code: a blue medium shirt and a black large shirt should not share one identifier. Keep the code short enough to read on a shelf label, avoid look-alike characters such as O and 0, and maintain a separate lookup that spells out the full product, size, colour, model, and condition.
Use the code consistently on receiving notes, stock counts, and picking records, while keeping customer-facing names clear rather than forcing shoppers to decode internal abbreviations. A simple spreadsheet can link a code to its listing and storage location; protect customer or supplier information by leaving it out of the code itself.
When an option is discontinued, mark its code inactive instead of assigning it to another item. Test the scheme by asking a second person to locate a sample unit from its code alone. If they pick the wrong variant, simplify the format or improve the lookup before using it across the catalogue.
