Product SKU (Stock Keeping Unit): A unique alphanumeric identifier assigned to a specific product or product variant, capturing attributes such as size, color, style, or packaging, and used to track inventory, sales, and stock movement; unlike universal codes such as UPCs, each company defines its own SKU scheme. In digital commerce platforms like Namazu Elements, a SKU is the store-facing identifier that players purchase and that maps to a product bundle defining the in-game items, currency, or rewards granted, with distinct SKUs typically registered per storefront such as the Apple App Store or Google Play.