A SKU (Stock Keeping Unit) is an internal identifier assigned to a specific product variant — including all attributes that make it distinct: size, color, bundle configuration, and condition. Two products that are identical except for color have different SKUs.
In repricing and pricing intelligence, SKU-level granularity is important because each variant may have a different cost basis, competitive landscape, and margin requirement. Treating all variants of a parent ASIN identically can lead to pricing decisions that are unprofitable for some variants while correct for others.